MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'BJ Disease' source. Mon, 06 Feb 2012 13:31:35 +0100 http://www.medworm.com/index.php?rid=5656180&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20112159 The semi-synthetic sulfated polysaccharide pentosan polysulfate (PPS) increases affinity between the aggrecan-degrading adamalysins with thrombospondin motifs (ADAMTSs) and their endogenous inhibitor, tissue inhibitor of metalloproteinases (TIMP)-3. Here we demonstrate that PPS mediates the formation of a high affinity trimolecular complex with ADAMTS-5 and TIMP-3. A TIMP-3 mutant that lacks extracellular matrix binding ability was insensitive to this affinity increase, and truncated forms of ADAMTS-5 that lack the Spacer domain had reduced PPS-binding ability and sensitivity to the affinity increase. PPS molecules composed of 11 or more saccharide units were 100-fold more effective than those of 8 saccharide units, indicating the involvement of extended or multiple protein interaction sit... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5656180 Fri, 03 Feb 2012 05:00:00 +0100 5656180 http://www.medworm.com/index.php?rid=5624470&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111779 The human protein Pontin, which belongs to the AAA+ family, is overexpressed in several cancers and its silencing in vitro leads to tumor cell growth arrest and apoptosis, making it a good target for cancer therapy. In particular, high levels of expression were found in hepatic tumors for which the therapeutic arsenal is rather limited. The 3D structure of Pontin had previously been resolved, revealing an hexameric assembly with one ADP molecule co-crystallized in each subunit. Using Vina, Drugscore and Xscore, structure-based virtual screening of 2,200 commercial molecules was conducted into the ATP binding site formed by a dimer of Pontin in order to prioritize the best candidates. Complementary to the in silico screening, a versatile and sensitive colorimetric assay was set up to... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5624470 Tue, 24 Jan 2012 05:00:00 +0100 5624470 http://www.medworm.com/index.php?rid=5603666&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111542 The malaria parasite Plasmodium falciparum is able to synthesize de novo pyridoxal-5-phosphate (PLP), the active form of vitamin B6. We show here that the de novo synthesized PLP is used by the parasite to detoxify singlet molecular oxygen (1O2), a highly destructive reactive oxygen species arising from hemoglobin digestion. The formation of singlet oxygen and the response of the parasite were monitored by life cell fluorescence microscopy, by transcription analysis and by determination of PLP levels in the parasite, respectively. Pull-down experiments of transgenic parasites overexpressing the vitamin B6 biosynthetic enzymes PfPdx1 and PfPdx2 clearly demonstrated an interaction of the two proteins in vivo which results in an elevated PLP level from 12.5 microM in wild-type parasites to 36... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5603666 Mon, 16 Jan 2012 05:00:00 +0100 5603666 http://www.medworm.com/index.php?rid=5603665&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20112124 Many diseases of ageing including Alzheimer’s Disease (AD) and type 2 diabetes (T2D) are strongly associated with common risk factors, such as hypertension, hyperglycaemia and hyperinsulinaemia, suggesting that there may be shared ageing mechanisms underlying these diseases, with scope to identify common cellular targets for therapy. Here we have studied insulin-like signalling properties of an experimental AD 8-hydroxyquinoline drug known as clioquinol. The insulin/IGF-1 signal transduction (IIS) kinase Akt/PKB inhibits the transcription factor FOXO1a by phosphorylating it on residues that trigger its exit from the nucleus and in 293 cells we found that clioquinol treatment induces similar effects. A key transcriptional response to IIS is inhibition of hepatic gluconeogenic gene ex... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5603665 Mon, 16 Jan 2012 05:00:00 +0100 5603665 http://www.medworm.com/index.php?rid=5592687&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111856 In conclusion, we identified that NFκB, Egr1, and Sp1 played important roles in regulation of basal Ngb expression via specific interactions with the mouse Ngb promoter. NFκB, Sp1 and HIF1α contributed to the upregulation of mouse Ngb gene expression under hypoxic conditions. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=5592687 Fri, 13 Jan 2012 05:00:00 +0100 5592687 http://www.medworm.com/index.php?rid=5592688&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111700 Protein Kinase D2 (PKD2) is a serine/threonine kinase activated by diacylglycerol in response to engagement of antigen receptors in lymphocytes. To explore PKD2 regulation and function in T cell antigen receptor (TCR) signal transduction we expressed TCR complexes with fixed affinity for self antigens in T cells of PKD2 null mice or mice deficient in PKD2 catalytic activity. We also developed a single cell assay to quantify PKD2 activation as T cells respond to developmental stimuli or engagement of a/b TCR complexes in vivo. Strikingly, PKD2 loss caused increases in thymic output, lymphadenopathy and splenomegaly in TCR transgenic mice. The precise magnitude and timing of PKD2 activation during T cell development is thus critical to regulate thymic homeostasis. PKD2 null T cells that exit... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5592688 Tue, 10 Jan 2012 05:00:00 +0100 5592688 http://www.medworm.com/index.php?rid=5500908&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111973 Access of therapeutic biomolecules to cytoplasmic and nuclear targets is hampered by the inability of these molecules to cross biological membranes. Approaches to overcome this hurdle involve cell penetrating peptides (CPPs) or protein transduction domains. Most of these require rather high concentrations to elicit cell penetrating functionality, are non-human, pathogen-derived or synthetic entities and may therefore not be tolerated or even immunogenic. We identified novel human protein derived CPPs by a combination of in-silico and experimental analyses: polycationic CPP candidates were identified in an in-silico library of all 30mer peptides of the human proteome. 60 of these peptides derived from extracellular proteins were evaluated experimentally. Cell viability and siRNA transfectio... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5500908 Tue, 13 Dec 2011 05:00:00 +0100 5500908 http://www.medworm.com/index.php?rid=5500909&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111166 In conclusion, conversion of HpETE to HETE is mediated by apoD M93, a process that may contribute to apoD antioxidant function. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=5500909 Mon, 12 Dec 2011 05:00:00 +0100 5500909 http://www.medworm.com/index.php?rid=5482761&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111741 In this study, we investigated whether the ubiquitously expressed p110a can also functionally interact with PTEN in cancer. Using genetic mouse models that mimic systemic administration of p110α- or p110b-selective inhibitors, we confirm that inactivation of p110b but not p110a inhibits prostate cancer development in PTEN+/- mice, but also find that p110a inactivation protects from glomerulonephritis, pheochromocytoma and thyroid cancer induced by PTEN loss. This indicates that p110a can modulate the impact of PTEN loss in disease and tumourigenesis. In primary and immortalised mouse fibroblast cell lines, both p110a and p110b controlled steady-state PIP3 levels and Akt signalling induced by heterozygous PTEN loss. In contrast, no correlation was found in primary mouse tissue... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5482761 Wed, 07 Dec 2011 05:00:00 +0100 5482761 http://www.medworm.com/index.php?rid=5473455&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111271 Epigenetic gene silencing is an important mechanism in the initiation and progression of cancer. Abnormal DNA CpG island hypermethylation and histone modifications are involved in aberrant silencing of tumor suppressor genes. Lysine-specific demethylase 1 (LSD1) was the first enzyme identified to specifically demethylate lysine 4 of histone H3 (H3K4). Methylated H3K4 is an important mark associated with transcriptional activation. The flavin adenine dinucleotide binding, amine oxidase domain of LSD1 is homologous to two polyamine oxidases, spermine oxidase and N1-acetylpolyamine oxidase. We have demonstrated that long chain polyamine analogues, the oligoamines, are inhibitors of LSD1. Here we report the synergistic effects of specific oligoamines in combination with 2-difluoromethylornithi... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5473455 Fri, 02 Dec 2011 05:00:00 +0100 5473455 http://www.medworm.com/index.php?rid=5464993&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111517 In conclusion, our study suggests that miR-17 plays an important role in CRC carcinogenesis by targeting RND3 and may be a therapeutic agent for CRC. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=5464993 Thu, 01 Dec 2011 05:00:00 +0100 5464993 http://www.medworm.com/index.php?rid=5447457&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100993 In this study, we show that the PS1-mediated (or possibly the PS2-mediated) signal is essential for the APP-mediated death in a gamma-secretase-independent manner and vice versa. MOCA (modifier of cell adhesion), originally identified as being a PS- and Rac1-binding protein, is a common downstream constituent of these neuronal death signals. The detailed molecular analysis indicates that MOCA is a key molecule of the AD-relevant neuronal death signals that links the PS-mediated death signal with the APP-mediated death signal at a point between Rac1 (or Cdc42) and ASK1. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=5447457 Thu, 24 Nov 2011 05:00:00 +0100 5447457 http://www.medworm.com/index.php?rid=5427829&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111798 In this study, we first purified vWF from HD-patients and then chemically characterized its oxidative state. Interestingly, HD-vWF contains high carbonyl levels and increased proportion of UL-vWF polymers, which are also more resistant to ADAMTS-13. Using targeted mass spectrometry techniques, we estimated that HD-vWF contains <10% of Met1606 in the sulphoxide form. We conclude that oxidation of Met1606, impairing ADAMTS-13 cleavage, results in the accumulation of UL-vWF polymers, which recruit and activate more efficiently platelets and bind more tightly to bacterial adhesins, thus contributing to the development of thrombotic and septic complications in CKD. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=5427829 Fri, 18 Nov 2011 05:00:00 +0100 5427829 http://www.medworm.com/index.php?rid=5417165&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111620 In this study, we provide evidence that rOrf8/EscI, a poorly characterized locus of enterocyte effacement-encoded protein, functions as the inner rod protein of the T3SS of enteropathogenic E. coli (EPEC). We demonstrated that EscI is essential for type III secretion and is also secreted as an early substrate of the T3SS. We found that EscI interacts with EscU, the integral membrane protein that is linked to substrate specificity switching, implicating EscI in the substrate-switching event. Furthermore, we showed that EscI self-associates and interacts with the outer membrane secretin, EscC, further supporting its function as an inner rod protein. Overall, our data suggest that EscI is the YscI/PrgJ/MxiI homolog in the T3SS of attaching and effacing pathogens. . (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=5417165 Thu, 17 Nov 2011 05:00:00 +0100 5417165 http://www.medworm.com/index.php?rid=5417164&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111145 This study focuses on the A13T (alanine to threonine) mutation in the human ventricular myosin regulatory light chain (RLC) that is associated with a rare FHC variant defined by mid ventricular obstruction and septal hypertrophy. Here, we generated heart specific transgenic (Tg) mice with ~10% of human A13T-RLC mutant replacing the endogenous mouse cardiac RLC. Histopathological examinations of longitudinal heart sections from Tg-A13T mice showed enlarged inter-ventricular septa and profound fibrotic lesions compared to Tg-WT, expressing the human ventricular RLC, or to non-Tg mice. Functional studies revealed an abnormal A13T-induced increase in isometric force production, no change in the force-pCa relationship and a decreased Vmax of the acto-myosin ATPase. In addition, a fluorescence-b... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5417164 Thu, 17 Nov 2011 05:00:00 +0100 5417164 http://www.medworm.com/index.php?rid=5417166&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111269 Airway inflammation in allergen-induced asthma is associated with eicosanoid release. These bioactive lipids exhibit anti- and pro-inflammatory activities with relevance to pulmonary pathophysiology. We hypothesized that sensitization/challenge using an extract from the ubiquitous fungus, Aspergillus fumigatus (Af), in a mouse model of allergic asthma would result in altered phospholipase gene expression, thus modulating the downstream eicosanoid pathway. We observed the most significant induction in the group IVC phospholipase A2 (cPLA2γ or PLA2G4C). Our results infer that Af extract can induce cPLA2γ levels directly in eosinophils while induction in lung epithelial cells is most likely a consequence of TNF-α secretion by Af-activated macrophages. The mechanism of TNF... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5417166 Tue, 15 Nov 2011 05:00:00 +0100 5417166 http://www.medworm.com/index.php?rid=5396484&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111464 Upon ras activation, ornithine decarboxylase (ODC) is markedly induced, and numerous studies suggest that ODC expression is controlled by Ras effector pathways. ODC is therefore a potential target in the treatment and prevention of Ras-driven tumors. We compared ODC mRNA translation profiles and stability in normal and Ras12V-transformed rat intestinal epithelial (RIE-1) cells. While translation initiation of ODC increased modestly in Ras12V cells, ODC RNA was stabilized 8-fold. Treatment with the specific mTORC1 inhibitor rapamycin or siRNA knockdown of mTOR destabilized the ODC message, but rapamycin had only a minor effect on ODC translation initiation. Inhibition of mTORC1 also reduced the association of the mRNA binding protein HuR with the ODC transcript. We have shown previously tha... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5396484 Thu, 10 Nov 2011 05:00:00 +0100 5396484 http://www.medworm.com/index.php?rid=5396485&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110846 This study describes AGE inhibition and the mechanism of action of new antiglycating agent, ellagic acid (EA), a flavonoid present in many dietary sources. Inhibition of AGE formation by EA was demonstrated with different proteins viz eye lens total soluble protein (TSP), hemoglobin (Hb), lysozyme and BSA using divergent glycating agents like fructose, ribose and methylglyoxal by a set of complementary methods. These results suggest that antiglycating action of EA seems to involve, apart from the inhibition of a few fluorescent AGE, predominantly inhibition of Nε-(carboxyethyl)lysine (CEL) through scavenging of dicarbonyl compounds. Further, MALDI-ToF/ToF analysis confirms inhibition of formation of CEL on lysozyme upon in vitro glycation by EA. Prevention of glycation-mediated &#x0... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5396485 Tue, 08 Nov 2011 05:00:00 +0100 5396485 http://www.medworm.com/index.php?rid=5374768&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111215 Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have been identified in PARK8, a major form of autosomal-dominantly inherited familial Parkinson’s disease, although the biochemical properties of LRRK2 are not fully understood. Recent reports proposed that LRRK2 predominantly exists as a homodimer based on the observation that LRRK2, with a theoretical mass of 280 kDa, migrates at 600 kDa position (p600 LRRK2) on native polyacrylamide gels. Here, we biochemically re-examined the nature of p600 LRRK2 and found that the p600 LRRK2 was fractionated with a single peak at ~272 kDa by ultracentrifugation on a glycerol gradient. In addition, the p600 LRRK2 behaved similarly to monomeric proteins upon two-dimensional electrophoretic separation. These results suggested the monomeri... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5374768 Wed, 02 Nov 2011 04:00:00 +0100 5374768 http://www.medworm.com/index.php?rid=5374769&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110314 BACH1, the product of the FANCJ gene mutated in Fanconi anemia patients from complementation group J, has been implicated in DNA repair and damage signalling. BACH1 exerts DNA helicase activities and physically interacts with BRCA1 and MLH1, which differentially control DNA double-strand break (DSB) repair processes. Our study shows that BACH1 plays a role in both homologous recombination (HR) and microhomology-mediated non-homologous end-joining (MMEJ) and reveals discrete mechanisms underlying modulation of these pathways. Our results indicate that BACH1 stimulates HR, which depends on the integrity of the helicase domain. Disruption of the BRCA1-BACH1 complex through BACH1 mutation compromised error-free NHEJ and accelerated error-prone MMEJ. Conversely, molecular changes in BACH1 abrog... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5374769 Fri, 28 Oct 2011 04:00:00 +0100 5374769 http://www.medworm.com/index.php?rid=5355106&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110795 Leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation (LBSL) is an autosomal recessive white matter disorder with slowly progressive cerebellar ataxia, spasticity and dorsal column dysfunction. Magnetic resonance imaging shows characteristic abnormalities in the cerebral white matter and specific brain stem and spinal cord tracts. LBSL is caused by mutations in the gene DARS2, which encodes mitochondrial aspartyl-tRNA synthetase. The selective involvement of specific white matter tracts in LBSL is striking since this protein is ubiquitously expressed. Almost all LBSL patients have one mutation in intron 2 of DARS2, affecting the splicing of the third exon. Using a splicing reporter construct, we find cell type-specific differences in the sensitivity to these... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5355106 Tue, 25 Oct 2011 04:00:00 +0100 5355106 http://www.medworm.com/index.php?rid=5343380&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111574 In this study we show that the malate-aspartate NADH shuttle is impaired in Saccharomyces cerevisiae frataxin-deficient cells (Δyfh1) due to decreased activity of cytosolic and mitochondrial isoforms of malate dehydrogenase and to complete inactivation of the mitochondrial aspartate aminotransferase (Aat1). A considerable decrease in the amount of mitochondrial acetylated proteins was observed in the Δyfh1 mutant compared to wild-type. Aat1 is acetylated in wild-type mitochondria and deacetylated in Δyfh1 mitochondria suggesting that inactivation could be due to this post-translational modification. Mutants deficient in iron-sulfur cluster assembly or lacking mitochondrial DNA also showed decreased activity of Aat1, suggesting that Aat1 inactivation was a secondary phe... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5343380 Thu, 20 Oct 2011 04:00:00 +0100 5343380 http://www.medworm.com/index.php?rid=5321234&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110282 In conclusion, mesothelin enhances ovarian cancer invasion by MMP-7 expression through the MAPK/ERK and JNK signal transduction pathways. Blocking the mesothelin-related pathway can be a potential strategy for inhibiting the growth of ovarian cancer. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=5321234 Fri, 14 Oct 2011 04:00:00 +0100 5321234 http://www.medworm.com/index.php?rid=5246006&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101909 The absence of Klotho (KL) in mice causes the development of disorders associated with human aging and decreased longevity, while increased expression prolongs lifespan. With age, KL protein levels decrease and keeping levels consistent may promote healthier aging and be disease modifying. Using the KL promoter to drive expression of luciferase, we conducted a high throughput screen to identify compounds that activate KL transcription. Hits were identified as compounds elevating luciferase expression at least 30%. Following validation for dose-dependent activation and lack of cytotoxicity, hit compounds were further evaluated in vitro by incubation with opossum kidney and Z310 rat choroid plexus cells, which express KL endogenously. All compounds elevated KL protein compared to control. To... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5246006 Thu, 22 Sep 2011 04:00:00 +0100 5246006 http://www.medworm.com/index.php?rid=5246007&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111637 Frataxin is a conserved mitochondrial protein deficient in patients with Friedreich’s ataxia. Frataxin has been implicated in control of iron homeostasis and Fe-S cluster assembly. In yeast or human mitochondria, frataxin interacts with components of the Fe-S cluster synthesis machinery, including the cysteine desulfurase (Nfs1), accessory protein (Isd11), and scaffold protein (Isu). Here we report that a single amino acid substitution (methionine to isoleucine) at position 107 in the mature form of Isu1 protein restored many deficient functions in ∆yfh1 or frataxin-depleted yeast cells. Iron homeostasis was improved such that soluble/usable mitochondrial iron was increased and accumulation of insoluble/non-usable iron within mitochondria was largely prevented. Cytochromes we... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5246007 Wed, 21 Sep 2011 04:00:00 +0100 5246007 http://www.medworm.com/index.php?rid=5203888&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110033 This study suggests of both rapamycin and PF-4708671's therapeutic value in treating human MI patients. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=5203888 Fri, 09 Sep 2011 04:00:00 +0100 5203888 http://www.medworm.com/index.php?rid=5203889&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110621 Late-onset neurodegenerative diseases are characterized by progressive accumulation of aggregation-prone proteins and global disruption of the proteostasis network, e.g. abnormal polyglutamine (polyQ) aggregation in Huntington's disease. Astragalus membranaceus polysaccharide (astragalan) has recently been shown to modulate aging and proteotoxic stress pathways. Using Caenorhabditis elegans models, we now show that astragalan not only reduces polyQ aggregation but also alleviates the associated neurotoxicity. We also reveal that astragalan can extend the adult lifespan of wild-type and polyQ nematodes, indicating a connection of its anti-aging benefit with the toxicity-suppressing effect. Further examination demonstrates that astragalan can extend the lifespan of daf-2 and age-1, but not d... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5203889 Mon, 05 Sep 2011 04:00:00 +0100 5203889 http://www.medworm.com/index.php?rid=5168722&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111050 The A118G single nucleotide polymorphism (SNP) of the human mu opioid receptor (hMOPR) gene OPRM1 results in an amino acid substitution (N40D). Subjects homozygous for G118 allele were reported to require higher morphine doses to achieve adequate analgesia and G118 allele was more prevalent among drug abusers. However, changes in the MOPR protein associated with this SNP are unknown. Using a knock-in mouse model (G/G mice) that possesses the equivalent nucleotide/amino acid substitution (N38D; A112G) of the A118G in the hMOPR gene , we investigated N-linked glycosylation status of thalamic and striatal MOPR in G/G mice vs A/A (wildtype) mice. The relative molecular mass (Mr) of MOPR determined with immunoblotting was lower in G/G mice than in A/A mice. Following treatment with PNGase F, wh... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5168722 Wed, 24 Aug 2011 23:00:00 +0100 5168722 http://www.medworm.com/index.php?rid=5155305&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110419 Salmonella typhimurium invades eukaryotic cells by re-arranging the host cell cytoskeleton. However, the precise mechanisms by which Salmonella induces cytoskeletal changes remain undefined. IQGAP1 is a scaffold protein that binds multiple proteins, including actin, the Rho GTPases Rac1 and Cdc42, and components of the mitogen activated protein kinase (MAPK) pathway. We have previously shown that optimal invasion of Salmonella into HeLa cells requires IQGAP1. Here, we use IQGAP1-null mouse embryonic fibroblasts (MEFs) and selected, well-characterized IQGAP1 mutant constructs to dissect the molecular determinants of Salmonella invasion. Knockout of IQGAP1 expression reduced Salmonella invasion into MEFs by 75%. Reconstituting IQGAP1-null MEFs with wild-type IQGAP1 completely rescued invasio... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5155305 Wed, 17 Aug 2011 23:00:00 +0100 5155305 http://www.medworm.com/index.php?rid=5129799&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101796 Mutations in the kinase domain of Anaplastic Lymphoma Kinase (ALK) have recently been shown to be important for the progression of the childhood tumor neuroblastoma. Here we investigate six of the putative reported constitutively active ALK mutations, in positions G1128A, I1171N, F1174L, R1192P, F1245C and R1275Q. Our analyses were performed in cell culture based systems with both mouse and human ALK mutant variants and subsequently in a Drosophila melanogaster model system. Our investigation addressed the transforming potential of the putative gain-of-function ALK mutations as well as their signalling potential and the ability of two ATP-competitive inhibitors, Crizotinib (PF-02341066) and NVP-TAE684, to abrogate ALK’s activity. The results presented here indicate that all mutation... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5129799 Sun, 14 Aug 2011 23:00:00 +0100 5129799 http://www.medworm.com/index.php?rid=5124291&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100739 In conclusion, here we have identified and thoroughly characterized a novel protein displaying high sequence similarity with PLI-γ molecule and possessing remarkable cytotoxic and antitumor effects, that can be exploited for potential pharmacological applications. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=5124291 Thu, 11 Aug 2011 23:00:00 +0100 5124291 http://www.medworm.com/index.php?rid=5116898&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20111333 Acquired drug resistance was found to be suppressed in doxorubicin resistant breast cancer cells (MCF7/Dx cells) after a pre-treatment with nitrosoglutathione (GSNO). The effect was accompanied by enhanced protein glutathionylation and accumulation of doxorubicin in the nucleus. Among the glutathionylated proteins we identified three members of the histone family; this is the first time that histone glutathionylation has been reported. Formation of the potential nitric oxide donor dinitrosyl diglutathionyl iron complex, bound to glutathione transferase (GST P1-1), was observed in both MCF7/Dx cells and drug-sensitive MCF7 cells, to a similar extent. In contrast, histone glutathionylation was found to be markedly increased in the resistant MCF7/Dx cells, which also showed 14-fold higher amo... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5116898 Wed, 10 Aug 2011 23:00:00 +0100 5116898 http://www.medworm.com/index.php?rid=5076207&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110977 Microsomal prostaglandin E synthase-1 (mPGES-1) is a newly recognized target for the treatment of inflammatory diseases. As the terminal enzyme of the prostaglandin production pathway, mPGES-1 inhibition may have a low risk of side effects. Inhibitors of mPGES-1 have attracted considerable attention as next-generation anti-inflammatory drugs. However, as mPGES-1 is a membrane protein, its enzymatic mechanism remains to be fully disclosed. We used molecular dynamics (MD) simulations, mutation analysis, hybrid experiments, and co-immunoprecipitation to investigate the conformation transitions of mPGES-1 during catalysis. mPGES-1 forms a homotrimer with three substrate binding sites (pockets). In the MD simulation, only one substrate molecule could bind to one of the pockets and form the acti... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5076207 Thu, 28 Jul 2011 23:00:00 +0100 5076207 http://www.medworm.com/index.php?rid=5068467&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110125 S49 mouse lymphoma cells undergo apoptosis in response to the alkyl-lysophospholipid (ALP) edelfosine, Fas/CD95 ligand (FasL) and DNA damage. Cells made resistant to ALP (S49AR) are defective in sphingomyelin synthesis and ALP uptake, and also have acquired resistance to FasL and DNA damage. However, these cells can be resensitized following prolonged culturing in the absence of ALP. The resistant cells show sustained ERK/Akt activity, consistent with enhanced survival signalling. In search of a common mediator of the observed cross-resistance, we found that S49AR cells lacked the PtdIns(3,4,5)P3 phosphatase SHIP-1, a known regulator of the Akt survival pathway. Resensitization of the S49AR cells restored SHIP-1 expression as well as phosphoinositide and sphingomyelin levels. Knockdown of ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5068467 Tue, 26 Jul 2011 23:00:00 +0100 5068467 http://www.medworm.com/index.php?rid=5048045&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110853 Cancer cells are hypersensitive to nutrient limitation because oncogenes constitutively drive glycolytic and tricarboxylic acid (TCA) cycle intermediates into biosynthetic pathways. Because the anaplerotic reactions that replace these intermediates are fueled by imported nutrients, the cancer cell’s ability to generate ATP becomes compromised under nutrient-limiting conditions. In addition, most cancer cells have defects in autophagy, the catabolic process that provides nutrients from internal sources when external nutrients are unavailable. Normal cells, in contrast, can adapt to nutrient stress that kills cancer cells by becoming quiescent and catabolic. We show that FTY720, a water soluble sphingolipid drug that is effective in many animal cancer models, selectively starves cance... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5048045 Sun, 17 Jul 2011 23:00:00 +0100 5048045 http://www.medworm.com/index.php?rid=5026676&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110555 The nitroxide tempol reduces tissue injury in animal models of inflammation by mechanisms that are not completely understood. Myeloperoxidase (MPO), which plays a fundamental role in oxidant production by neutrophils, is an important target for anti-inflammatory action. By amplifying the oxidative potential of hydrogen peroxide, MPO produces hypochlorous acid and radicals through the oxidizing intermediates MPO-I and MPO-II. Previously, we reported that tempol reacts with MPO-I and MPO-II with second-order rate constants similar to those of tyrosine. However, we noticed that tempol inhibits the chlorinating activity of MPO, in contrast to tyrosine. Thus, we studied the inhibition of MPO-mediated taurine chlorination by tempol at pH 7.4 and re-determined the kinetic constants of the reactio... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5026676 Tue, 12 Jul 2011 23:00:00 +0100 5026676 http://www.medworm.com/index.php?rid=5017638&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110725 This study was conducted to verify whether caffeine is beneficial for improving leukemia therapy. Co-treatment with adaphostin (Bcr/Abl inhibitor) was found to potentiate caffeine-induced Fas/FasL up-regulation. Although adaphostin did not elicit ASK1-mediated phosphorylation of p38 MAPK and JNK, co-treatment with adaphostin notably increased p38 MAPK/JNK activation in caffeine-treated cells. Suppression of p38 MAPK and JNK abrogated Fas/FasL up-regulation in caffeine- and caffeine/adaphostin-treated cells. Compared with caffeine, adaphostin markedly suppressed Akt/ERK-mediated MKP-1 protein expression in K562 cells. MKP-1 down-regulation eventually elucidated the enhanced effect of adaphostin on p38 MAPK/JNK activation and subsequent Fas/FasL up-regulation in caffeine-treated cells. Knock... BJ Disease journals http://www.medworm.com/rss/comments.php?id=5017638 Sun, 10 Jul 2011 23:00:00 +0100 5017638 http://www.medworm.com/index.php?rid=4974500&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110926 To study phospholamban (PLB) inhibition of the cardiac Ca2+ pump (SERCA2a), a fusion protein (SER-20G-PLB) was engineered by tethering SERCA2a with PLB through a 20 glycine-residue chain, allowing the PLB-tether either to bind to or dissociate from inhibition site on SERCA2a. When expressed in insect cells, SER-20G-PLB produced active Ca2+ uptake, which was stimulated by the anti-PLB antibody, both similar to that occurred with the control sample co-expressing WT-SERCA2a and WT-PLB. The KCa values of Ca2+-dependent ATPase were similar for SER-20G-PLB (0.29±0.02 µM) and for the control sample (0.30±0.02 µM), both greater than 0.17±0.01 µM for WT-SERCA2a expressed alone. Thus, SER-20G-PLB retains a fully active Ca2+ pump, ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4974500 Mon, 27 Jun 2011 23:00:00 +0100 4974500 http://www.medworm.com/index.php?rid=4974499&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110150 Lafora progressive myoclonus epilepsy (Lafora disease; LD) is a fatal autosomal recessive neurodegenerative disorder caused by loss-of-function mutations in either the EPM2A gene, encoding the dual specificity phosphatase laforin, or the EPM2B gene, encoding the E3-ubiquitin ligase malin. Previously, we and others showed that laforin and malin form a functional complex that regulates multiple aspects of glycogen metabolism, and that the interaction between laforin and malin is enhanced by conditions activating AMP-activated protein kinase (AMPK). Here, we demonstrate that laforin is a phosphoprotein, as indicated by two-dimensional electrophoresis, and we identify Ser25 as the residue involved in this modification. We also show that Ser25 is phosphorylated both in vitro and in vivo by AMPK... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4974499 Mon, 27 Jun 2011 23:00:00 +0100 4974499 http://www.medworm.com/index.php?rid=4967363&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110750 Amyloid-Beta peptide (Ab) assembles to form amyloid fibres that accumulate in senile plaques associated with Alzheimer’s disease (AD). The major constituent, a 42-residue Ab peptide, has the propensity to assemble and form soluble and potentially cytotoxic oligomers as well as ordered, stable amyloid fibres. It is widely believed that the cytotoxicity is a result of the formation of transient soluble oligomers. This observed toxicity maybe associated with the ability of oligomers to associate with and cause permeation of lipid membranes. Here, we have investigated the ability of oligomeric and fibrillar Ab42 to simultaneously associate with and affect the integrity of biomimetic membranes in vitro. Surface Plasmon field enhanced Fluorescence spectroscopy reveals that the binding of ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4967363 Thu, 23 Jun 2011 23:00:00 +0100 4967363 http://www.medworm.com/index.php?rid=4951172&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110672 The cystic fibrosis transmembrane conductance regulator (CFTR) gene shows a complex temporal and spatial pattern of expression that is controlled by multiple cis-acting elements interacting with the basal promoter. While significant progress has been made towards understanding these genomic elements, there have been no reports of post-transcriptional regulation of CFTR by microRNAs (miRNAs). Here, we identify two miRNAs, hsa-miR-145 and hsa-miR-494, which regulate CFTR expression by directly targeting discrete sites in the CFTR 3' UTR. We show that at least twelve miRNAs are capable of repressing endogenous CFTR mRNA expression in the Caco-2 cell line. Ten of these also inhibit expression of a reporter construct containing the CFTR 3' UTR in one or more cell lines, and five repress endogen... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4951172 Sun, 19 Jun 2011 23:00:00 +0100 4951172 http://www.medworm.com/index.php?rid=4919882&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101986 L-Trifluoromethionine (TFM), a potential prodrug, was reported to be toxic toward human pathogens that express L-methionine γ-lyase (MGL; EC: 4.4.1.11), a pyridoxal phosphate-containing enzyme that converts L-methionine to α-ketobutyrate, ammonia and methyl mercaptan. It has been hypothesized that the extremely reactive thiocarbonyl difluoride is produced when the enzyme acts upon TFM, resulting in cellular toxicity. The potential application of the fluorinated thiomethyl group in other areas of biochemistry and medicinal chemistry requires additional studies. Therefore a detailed investigation of the theoretical and experimental chemistry and biochemistry of these fluorinated groups (CF3S- and CF2HS-) has been undertaken to trap and identify chemical intermediates produced b... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4919882 Thu, 09 Jun 2011 23:00:00 +0100 4919882 http://www.medworm.com/index.php?rid=4910203&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101653 Hepatocellular carcinoma (HCC) is among the most common and lethal cancers worldwide with a poor prognosis mainly due to a high recurrence rate and chemotherapy resistance. Arsenic trioxide (ATO) is a multi-target drug that has been effectively used as an anticancer drug in acute promyelocytic leukemia. However, a phase II trial involving patients with HCC indicates that the use of arsenic as a single agent is not effective against HCC. TG-interacting factor (TGIF) is a transcriptional corepressor that interferes with TGF-b signaling which plays a growth-inhibitory role in HCC. In the present study, we demonstrated that ATO induced hepatocellular apoptosis via TGF-b/Smad signaling and leaded to downstream induction of p21WAF1/CIP1 (p21). However, ATO could also induce TGIF expression via p... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4910203 Mon, 06 Jun 2011 23:00:00 +0100 4910203 http://www.medworm.com/index.php?rid=4900975&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110566 We describe a new approach, involving LCxMS/MS analysis of sphingolipids based on both mass and hydrophobicity, and use this method to characterize the sphingomyelin (SM), ceramide, and galactosylceramide (GalCer) content of hippocampus from Alzheimer’s Disease (AD) and control subjects. Using a mathematical relationship we exclude the influence of sphingolipid mass on retention time, and generate two-dimensional plots that facilitate accurate visualization and characterization of the different ceramide moieties within a given sphingolipid class, because related molecules align horizontally or vertically on the plots. Major brain GalCer species that differ in mass by only 0.04 Da were easily differentiated on the basis of their hydrophobicity. The importance of our method’s c... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4900975 Thu, 02 Jun 2011 23:00:00 +0100 4900975 http://www.medworm.com/index.php?rid=4870562&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20102096 Bile acids from duodenogastric reflux promote inflammation and increase the risk for gastro-esophageal cancers. Farnesoid X receptor (FXR) is a transcription factor regulated by bile acids, such as chenodeoxycholic acid (CDCA). FXR protects the liver and the intestinal tract against bile acid overload, however, a functional role for FXR in the stomach has not been described. We detected FXR expression in the normal human stomach and in gastric cancer (GC). FXR mRNA and protein were also present in the human GC cell lines MKN45 and SNU5 but not in AGS. Transfection of FXR into AGS cells protected against TNFa-induced cell damage. We identified Keratin 13 (K13), an anti-apoptotic protein of desmosomes, as a novel CDCA-regulated FXR-target gene. FXR bound to a conserved regulatory element in ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4870562 Thu, 26 May 2011 23:00:00 +0100 4870562 http://www.medworm.com/index.php?rid=4827461&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110343 In this study, we found that ectopic expression of PLU1 enhanced the invasive potential of the weakly invasive cells dependent on its demethylase activity. PLU1 was shown to repress the expression of KAT5 gene through its histone H3K4 demethylation on the promoter. The regulation of KAT5 by PLU1 was suggested to be responsible for the PLU1-induced cell invasion. First, knockdown of KAT5 similarly increased the invasive potential of the cells. Second, knockdown of PLU1 in the highly invasive cancer cells increased KAT5 expression and reduced the invasive activity. Third, simultaneous knockdown of KAT5 partially relieved the suppression of cell invasion imposed by PLU1 knockdown. Finally, we found that CD82, which was transcriptionally regulated by KAT5, might be a candidate effector of cell... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4827461 Sun, 15 May 2011 23:00:00 +0100 4827461 http://www.medworm.com/index.php?rid=4811815&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110520 An understanding of the mechanism that regulates the cardiac differentiation of pluripotent stem cells is necessary for the effective generation and expansion of cardiomyocytes as cell therapy products. Here we have identified genes that modulate the cardiac differentiation of pluripotent embryonic cells. We isolated P19CL6 cell sublines that possess distinct properties in cardiomyogenesis and extracted 24 cardiomyogenesis-related candidate (CMR) genes correlated with cardiomyogenesis using a transcriptome analysis. Knockdown of the CMR genes by RNAi revealed that 18 CMR genes influence spontaneous contraction or transcript levels of cardiac marker genes in embryonal carcinoma (EC) cells. We also performed knockdown of the CMR genes in mouse embryonic stem (ES) cells and induced in vitro c... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4811815 Mon, 09 May 2011 23:00:00 +0100 4811815 http://www.medworm.com/index.php?rid=4801522&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110347 Glycogen synthase kinase-3β (GSK-3β), a crucial tau kinase, negatively regulates protein phosphatase-2A (PP2A), the most active tau phosphatase that is suppressed in the brain of Alzheimer disease (AD). However the molecular mechanism is not understood. Here we found that activation of GSK-3β stimulates the inhibitory phosphorylation of PP2A at tyrosine-307 (pY307-PP2A), whereas inhibition of GSK-3β decreased the level of pY307-PP2A both in vitro and in vivo. GSK-3β is a Ser/Thr kinase that can not phosphorylate tyrosine directly, therefore we measured protein tyrosine phosphatase 1B (PTP1B) and Src, a tyrosine kinase. We found that GSK-3β can modulate both PTP1B and Src, however only knockdown of PTP1B but not Src by siRNA eliminates the effects o... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4801522 Sun, 08 May 2011 23:00:00 +0100 4801522 http://www.medworm.com/index.php?rid=4794140&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110276 In this study we first assess the substrate specificity of TTBK2 and demonstrate that it has an unusual preference for a phosphotyrosine at the +2 position relative to the phosphorylation site. We elaborate a peptide substrate (TTBKtide, RRKDLHDDEEDEAMSIYpA) that can be employed to quantify TTBK2 kinase activity. Through modelling and mutagenesis we identify a putative phosphate priming-groove within the TTBK2 kinase domain. We demonstrate that SCA11 truncating mutations promote TTBK2 protein expression, suppress kinase activity and lead to enhanced nuclear localisation. We generate an SCA11-mutation-carrying knock-in mouse and show that this leads to inhibition of endogenous TTBK2 protein kinase activity. Finally, we find that in homozygosity, the SCA11 mutation causes embryonic le... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4794140 Thu, 05 May 2011 23:00:00 +0100 4794140 http://www.medworm.com/index.php?rid=4794139&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110510 We previously demonstrated that the complex bis[(2-oxindol-3-ylimino)-2-(2-aminoethyl)pyridine-N,N’]copper(II), named [Cu(isaepy)2], induces AMPK-dependent/p53-mediated apoptosis in tumour cells by targeting mitochondria. Here, we reveal that p38MAPK is the molecular link of the phosphorylative cascade connecting AMPK to p53. Transfection of SH-SY5Y with a dominant negative mutant of AMPK results in apoptosis decrease, and a significant reduction of phospho-active p38MAPK and p53. Similarly, reverse genetics of p38MAPK yields a reduction of p53 and decreases apoptotic extent, confirming an exclusive hierarchy of activation that proceeds via AMPK/p38MAPK/p53. Fuel supplies counteract [Cu(isaepy)2]-induced apoptosis and AMPK/p38MAPK/p53 activation, with glucose being the most effectiv... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4794139 Thu, 05 May 2011 23:00:00 +0100 4794139 http://www.medworm.com/index.php?rid=4641444&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110028 In this report, we demonstrate binding of HuR to a 288 bp fragment in the 3' untranslated region (UTR) of survivin mRNA in human esophageal epithelial cells. Unexpectedly, over-expression of HuR led to a decrease in survivin expression. This was associated with decreased survivin mRNA and promoter activity, suggesting decreased transcription. Levels of p53, a negative transcriptional regulator of survivin, increased following HuR over-expression, in conjunction with enhanced p53 mRNA stability. Silencing p53 prior to HuR over-expression resulted in increased survivin protein and mRNA stability. These results demonstrate that, in the absence of p53, HuR over-expression results in increased survivin mRNA stability and protein expression. This provides an additional explanation for the increa... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4641444 Sun, 27 Mar 2011 23:00:00 +0100 4641444 http://www.medworm.com/index.php?rid=4635817&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101723 There is a wide inter-individual variation in PARP activity, which may have implications for health. We investigated if the variation (i) is due to polymorphisms in the PARP-1 gene or PARP-1 protein expression and (ii) affects patients’ response to anticancer treatment. We studied 56 healthy volunteers (HV) and 118 cancer patients (CP), with supporting in vivo experiments. PARP activity ranged between 10–2600 pmol PAR/106 cells and expression between 0.02–1.55 ng PARP-1/µg protein. PARP-1 expression correlated with activity in HV (R2=0.19, P=0.003) and CP (R2=0.06, P=0.01). A short CA repeat in the promoter was significantly associated with increased cancer risk (OR, 5.22; 95% CI, 1.79–15.24). PARP activity was higher in men than women (P=0.04) in the ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4635817 Fri, 25 Mar 2011 00:00:00 +0100 4635817 http://www.medworm.com/index.php?rid=4610140&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20110062 NFATc1, a key transcription factor, plays a role in regulating expression of osteoclast-specific downstream target genes such as TRAP and OSCAR. It has been shown that RANKL induces NFATc1 expression during osteoclastogenesis at a transcriptional level. Herein, we demonstrate that RANKL increases NFATc1 protein levels by post-translational modification. RANKL stimulates NFATc1 acetylation via histone acetyltransferases (HATs) such as p300 and p300/CREB binding protein-associated factor (PCAF), thereby stabilizing NFATc1 proteins. PCAF physically interacts with NFATc1 and directly induces NFATc1 acetylation and stability, subsequently increasing the transcriptional activity of NFATc1. In addition, RANKL-mediated NFATc1 acetylation is increased by the histone deacetylase (HDAC) inhibitors so... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4610140 Fri, 18 Mar 2011 00:00:00 +0100 4610140 http://www.medworm.com/index.php?rid=4605108&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101957 Oxidized cytochrome c (Cyt-c) is a powerful superoxide scavenger within the mitochondrial intermembrane space, the importance of this role in situ has not been well explored. Here we investigate this with particular emphasis on whether loss of Cyt-c from mitochondria during heart ischaemia may mediate the increased production of reactive oxygen species during subsequent reperfusion that induces mitochondrial permeability transition pore (mPTP) opening. Mitochondrial Cyt-c depletion was induced in vitro with digitonin, or by 30 minutes ischaemia of the perfused rat heart. Control and Cyt-c-deficient mitochondria were incubated with mixed respiratory substrates and an ADP-regenerating system (State 3.5) to mimic physiological conditions. This contrasts with most published studies performed w... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4605108 Thu, 17 Mar 2011 00:00:00 +0100 4605108 http://www.medworm.com/index.php?rid=4590187&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101754 In conclusion, IGF-1 activates MAT2A transcription by both known and novel pathways. YY1 represses MAT2A expression. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=4590187 Tue, 15 Mar 2011 00:00:00 +0100 4590187 http://www.medworm.com/index.php?rid=4549217&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101512 Mest/Peg1 is an imprinted gene that plays important roles in embryo development, although its biochemical role has not been determined. Ectopic expression of Mest/Peg1 inhibited Wnt-mediated reporter activity by enhancing the ubiquitination of b-catenin. The maturation and plasma membrane localization of the Wnt co-receptor LRP6, which are both necessary for Wnt signaling, were blocked by the expression of Mest/Peg1. Mest/Peg1 inhibited maturation of LRP6 by controlling the glycosylation of LRP6. Knockdown of Mest/Peg1, which might enhance Wnt signaling, blocked adipogenic differentiation of 3T3-L1 cells. Overall, our data suggest that Mest/Peg1 is a novel regulator of Wnt/b-catenin signaling during adipogenic differentiation. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=4549217 Fri, 04 Mar 2011 00:00:00 +0100 4549217 http://www.medworm.com/index.php?rid=4539957&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101891 Hepatic glucose metabolism is strongly influenced by oxidative stress and pro-inflammatory stimuli. Paraoxonase 2 (PON2), an enzyme with undefined antioxidant properties, protects against atherosclerosis. PON2-deficient (PON2-def) mice have elevated hepatic oxidative stress coupled with an exacerbated inflammatory response from PON2-deficient macrophages. In this paper, we demonstrate that PON2-deficiency is associated with inhibitory insulin-mediated phosphorylation of hepatic insulin receptor substrate 1 (IRS-1). Unexpectedly, we observed a marked improvement in the hepatic IRS-1 phosphorylation state in PON2-def/apoE-/- mice, relative to apoE-/- mice. Factors secreted from activated macrophage cultures derived from PON2-def and PON2-def/apoE-/- are sufficient to modulate insulin signali... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4539957 Wed, 02 Mar 2011 00:00:00 +0100 4539957 http://www.medworm.com/index.php?rid=4535371&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101059 Congenital muscular dystrophies have a broad spectrum of genotypes and phenotypes and there is a need for a better biochemical understanding of this group of diseases in order to aid diagnosis and treatment. Several mutations resulting in these diseases cause reduced O-mannosyl glycosylation of glycoproteins, including alpha-dystroglycan. The enzyme protein-O-mannose N-acetylglucosaminyltransferase 1 (POMGnT1; EC 2.4.1.-) catalyzes the transfer of N-acetylglucosamine to O-linked mannose of a-dystroglycan, and affect glycosyltransferases or glycosyltransferase-like genes. Here we describe the biochemical characterization of 14 clinical mutants of the glycosyltransferase POMGnT1, which have been linked to Muscle-Eye-Brain disease or similar conditions. Truncated mutant variants of the human ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4535371 Tue, 01 Mar 2011 00:00:00 +0100 4535371 http://www.medworm.com/index.php?rid=4531320&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100884 Apert syndrome (AS) is a congenital disease composed of skeletal, visceral and neural abnormalities, caused by dominant-acting mutations in FGFR2. Multiple FGFR2 splice variants are generated through alternative splicing, including premature termination codon (PTC)-containing transcripts that are normally eliminated via the nonsense mediated decay (NMD) pathway. We have discovered that a soluble truncated FGFR2 molecule encoded by a PTC-containing transcript is upregulated and persists in tissues of an Apert syndrome mouse model. We have termed this IIIa-TM as it arises from aberrant splicing of FGFR2 exon 7 (IIIa) into exon 10 (transmembrane domain). IIIa-TM is glycosylated and can modulate the binding of FGF1 to FGFR2 molecules in BIAcore binding assays. We also show that IIIa-TM can neg... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4531320 Mon, 28 Feb 2011 00:00:00 +0100 4531320 http://www.medworm.com/index.php?rid=4521362&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101685 Nicotinamide N-methyltransferase (NNMT, E.C. 2.1.1.1) catalyses the N-methylation of nicotinamide to 1-methylnicotinamide. NNMT expression is significantly elevated in a number of cancers, and we have previously demonstrated that NNMT expression is significantly increased in the brains of patients who have died of Parkinson’s disease. To investigate the cellular effects of NNMT overexpression, we overexpressed NNMT in the SH-SY5Y cell-line, a tumour-derived human dopaminergic neuroblastoma cell-line with no endogenous expression of NNMT. NNMT expression significantly decreased SH-SY5Y cell death, which correlated with increased intracellular ATP content, ATP:ADP ratio, Complex I activity and a reduction in the degradation of the NDUFS3 subunit of Complex I. These effects were replic... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4521362 Fri, 25 Feb 2011 00:00:00 +0100 4521362 http://www.medworm.com/index.php?rid=4506580&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101908 DS (Down’s syndrome) is the most common human aneuploidy associated with mental retardation and early neurodegeneration. Mitochondrial dysfunction has emerged as a crucial factor in the pathogenesis of numerous neurological disorders including DS, but the cause of mitochondrial damage remains elusive. In this research, we identified new molecular events involved in mitochondrial dysfunction which could play a role in DS pathogenesis. We analyzed mitochondrial respiratory chain function in DS-HSF (human foetal skin fibroblasts with chromosome 21 trisomy) and found a selective deficit in the catalytic efficiency of mitochondrial complex I. Complex I deficit was associated with a decrease in cAMP-dependent phosphorylation of 18-kDa subunit of the complex, due to a decrease in PKA (prot... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4506580 Tue, 22 Feb 2011 00:00:00 +0100 4506580 http://www.medworm.com/index.php?rid=4459149&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101548 Whooping cough (pertussis) is a highly contagious, acute respiratory illness of humans caused by the gram-negative bacterial pathogen Bordetella pertussis. The autotransporter (AT) BrkA is an important B. pertussis virulence factor that confers serum resistance and mediates adherence. Here we present the crystal structure of B. pertussis BrkA β domain at 3Å resolution. Special features are a hairpin-like structure formed by the external loop L4, which is observed fortuitously sitting inside the pore of the crystallographic adjacent β domain; and a previously undiscovered hydrophobic cavity formed by patches on the loop L4 and β-strands S5 and S6. This adopts an ubiquitous structure characteristic of all AT β domains. Mutagenesis studies have demonstrated ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4459149 Thu, 10 Feb 2011 00:00:00 +0100 4459149 http://www.medworm.com/index.php?rid=4428366&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101614 Decidualization is a biological and morphological process occurring in human endometrial stromal (hES) cells. We previously reported that phospholipase D1 (PLD1) plays an important role in cAMP-induced decidualization of hES cells. In the present study, we focused on how PLD1 expression is upregulated during decidualization. Treatment with protein kinase A (PKA) inhibitors (Rp-cAMP or H89) or a Ras inhibitor (manumycin) partially inhibited PLD1 expression and deciduas formation in response to cAMP treatment. Interestingly, dual inhibition of PKA and Ras completely inhibited PLD1 expression and cAMP-induced decidualization. These results suggest that PLD1 expression during decidualization is controlled additively by PKA and Ras. Use of inhibitors showed that ERK, a downstream effecter of Ra... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4428366 Wed, 02 Feb 2011 00:00:00 +0100 4428366 http://www.medworm.com/index.php?rid=4398735&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101867 In conclusion, alterations in sphingolipid, rather than phospholipid, metabolism are more likely implicated in the defective protein trafficking, and enhanced ER stress and apoptosis, of lipotoxic b-cells. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=4398735 Tue, 25 Jan 2011 00:00:00 +0100 4398735 http://www.medworm.com/index.php?rid=4370200&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20102071 Chronic hepatitis B is a disease of the liver that can progress to cirrhosis and liver cancer. The hepatitis B virus X (HBx) protein of hepatitis B virus is a multifunctional regulator that induces endoplasmic reticulum (ER) stress by previously unknown mechanism. ER stress plays a critical role in inflammatory induction and cyclooxygenase-2 (COX2) is an important mediator of this inflammation. Here, we demonstrate the molecular mechanisms of HBx on induction of ER stress and COX2 expression. In addition, HBx protein reduced expression of enzymes, which are involved in mitochondrial β-oxidation of fatty acids, and the mitochondrial inner membrane potential. The reduction of intracellular ATP levels by HBx induced the unfolded protein response and COX2 expression through the eIF2&#x0... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4370200 Wed, 19 Jan 2011 00:00:00 +0100 4370200 http://www.medworm.com/index.php?rid=4336915&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101410 p38α MAP kinase plays an important tumor suppressor role, which is mediated by both its negative effect on cell proliferation and its pro-apoptotic activity. Surprisingly, most tumor suppressor mechanisms coordinated by p38α have been reported to occur at the post-translational level. This contrasts with the important role of p38α in the regulation of transcription and the profound changes in gene expression that normally occur during tumorigenesis. We have analyzed whole genome expression profiles of Ras-transformed wild-type and p38α-deficient cells and have identified 202 genes that are potentially regulated by p38α in transformed cells. Expression analysis has confirmed the regulation of these genes by p38α in tumors, and functional validation ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4336915 Wed, 12 Jan 2011 00:00:00 +0100 4336915 http://www.medworm.com/index.php?rid=4336916&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101987 Metabolic complications arising from excessive fructose consumption are increasing dramatically even in young children but little is known about ontogenetic mechanisms regulating GLUT5. GLUT5 expression is low postnatally and does not increase, unless luminal fructose and systemic glucocorticoids are present, until < 14 d of age, suggesting substrate-inducible, age- and hormone-sensitive regulation. We perfused intestines of 10 and 20 d old-rats with either fructose or glucose then analyzed binding of RNA polymerase II (pol II) and the glucocorticoid receptor (GR) as well as acetylation of histones H3 and H4 by chromatin immunoprecipitation. Abundance of GLUT5 mRNA increased only with fructose perfusion and age, a pattern that matches that of pol II binding and H3 acetylation to the GLU... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4336916 Tue, 11 Jan 2011 00:00:00 +0100 4336916 http://www.medworm.com/index.php?rid=4317764&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100655 Insulin secretion from pancreatic ß-cells is controlled by complex metabolic and energetic changes provoked by exposure to metabolic fuels. Perturbations in these processes lead to impaired insulin secretion, the ultimate cause of Type 2 Diabetes. To increase our understanding of stimulus-secretion coupling and metabolic processes potentially involved in the pathogenesis of Type 2 Diabetes, a comprehensive investigation of the metabolic response in the glucose-responsive INS-1 832/13 and glucose-unresponsive INS-1 832/2 β-cell lines was performed. For this metabolomics analysis, we used gas chromatography/mass spectrometry combined with multivariate statistics. We found that perturbed secretion in the 832/2 line was characterized by disturbed coupling of glycolytic and TCA-cy... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4317764 Thu, 06 Jan 2011 00:00:00 +0100 4317764 http://www.medworm.com/index.php?rid=4313446&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101772 A male infertility-linked human PLCζ mutation introduced into mouse PLCζ completely abolishes both in vitro PIP2 hydrolysis activity and the ability to trigger in vivo Ca2+ oscillations in mouse eggs. Wild-type PLCζ initiated a normal pattern of Ca2+ oscillations in eggs in the presence of 10-fold higher mutant PLCζ suggesting that infertility is not mediated by a dominant-negative mechanism. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=4313446 Wed, 05 Jan 2011 00:00:00 +0100 4313446 http://www.medworm.com/index.php?rid=4313445&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101485 Hyperphosphorylation of tau is a hallmark of Alzheimer’s disease and other tauopathies. Although the mechanisms underlying hyperphosphorylation are not fully understood, cellular stresses such as impaired energy metabolism are thought to influence the signalling cascade. The AMPK-related kinases, MARK and BRSK, have been implicated in tau phosphorylation but are insensitive to activation by cellular stress. Here we show that AMPK itself phosphorylates tau on a number of sites including S262 and S396, altering microtubule binding of tau. In primary mouse cortical neurons, CaMKKβ activation of AMPK in response to β-amyloid (Aβ1-42) leads to increased phosphorylation of tau at S262/S356 and S396. Activation of AMPK by Aβ1-42 is inhibited by memantine, a part... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4313445 Wed, 05 Jan 2011 00:00:00 +0100 4313445 http://www.medworm.com/index.php?rid=4280577&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101585 Plasminogen activator inhibitor-1 (PAI-1) is a key physiological inhibitor of fibrinolysis. Previously, we reported placenta growth factor (PlGF) mediated transcriptional upregulation of PAI-1 mRNA expression via activation of hypoxia-inducible factor-1α and activator protein-1 in human pulmonary microvascular endothelial cells (HPMVEC); which resulted in elevated PAI-1 in humans with sickle cell anemia (SCA). Herein, we identified the role of post-transcriptional mechanism(s) of PlGF-mediated accumulation of PAI-1 mRNA in HPMVEC by examining the role of microRNAs in PlGF-induced PAI-1 mRNA stability. Our results show reduced expression of miR-30c and miR-301a, but not of miR-99a in response to PlGF, which have evolutionarily conserved binding sites in the 3’-untranslated reg... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4280577 Wed, 22 Dec 2010 00:00:00 +0100 4280577 http://www.medworm.com/index.php?rid=4241017&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101456 Previously, we demonstrated that sog9 cells, a murine L cell mutant, are deficient in the expression of chondroitin 4-O-sulfotransferase-1 (C4ST-1) and that they synthesize fewer and shorter chondroitin sulfate (CS) chains. These results suggested that C4ST-1 regulates not only 4-O-sulfation of CS but also the length and amount of CS chains; however, the mechanism remains unclear. Here, we demonstrated that C4ST-1 regulated the chain length and amount of CS in cooperation with chondroitin N-acetylgalactosaminyltransferase 2 (ChGn-2). Overexpression of ChGn-2 increased the length and amount of CS chains in L cells, but not in sog9 mutant cells. Knockdown of ChGn-2 resulted in a decrease in the amount of CS in L cells in a manner proportional to ChGn-2 expression levels, while the introducti... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4241017 Wed, 08 Dec 2010 00:00:00 +0100 4241017 http://www.medworm.com/index.php?rid=4236755&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101701 Members of the IκB kinase (IKK) family play a central role in innate immunity by inducing NFκB- and IRF-dependent gene transcription programmes required for the production of pro-inflammatory cytokines and interferons. However, the molecular mechanisms that activate these protein kinases and their complement of physiological substrates remain poorly defined. Using MRT67307, a novel inhibitor of IKKε/TBK1 and BI605906, a novel inhibitor of IKKβ, we demonstrate that two different signalling pathways participate in the activation of the IKK-related protein kinases by ligands that activate the IL-1, TLR3 and TLR4 receptors. One signalling pathway is mediated by the canonical IKKs, which directly phosphorylate and activate IKKε and TBK1, whereas the second pat... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4236755 Tue, 07 Dec 2010 00:00:00 +0100 4236755 http://www.medworm.com/index.php?rid=4218749&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101902 Mutations in the nuclear gene coding for the mitochondrial aspartyl-tRNA synthetase, a key enzyme for mitochondrial translation, are correlated with leukoencephalopathy. Ser45 to Gly45 mutation is located in the predicted targeting signal of the protein. We demonstrate here, by in vivo and in vitro approaches, that this pathology-related mutation impairs the import process across mitochondrial membranes. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=4218749 Wed, 01 Dec 2010 00:00:00 +0100 4218749 http://www.medworm.com/index.php?rid=4178497&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101561 We report here the cloning of C. elegans cat-2 full-length cDNA and a detailed biochemical characterization of the encoded CAT-2 protein. Similar to other THs, C. elegans CAT-2 is composed of an N-terminal regulatory domain followed by a catalytic domain and a C-terminal oligomerization domain and shows high substrate specificity for L-Tyr. Likewise to human TH (hTH), CAT-2 is tetrameric and is phosphorylated at Ser35 (equivalent to Ser40 in hTH) by cAMP-dependent protein kinase. However, CAT-2 is devoid of characteristic regulatory mechanisms present in hTH, such as negative cooperativity for the cofactor, substrate inhibition or feed-back inhibition exerted by catecholamines, end products of the pathway. Thus, TH activity in C. elegans displays a weaker regulation in comparison with the ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4178497 Thu, 18 Nov 2010 00:00:00 +0100 4178497 http://www.medworm.com/index.php?rid=4158232&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101204 Moorella thermoacetica pyrophosphatase (mtCBS-PPase) contains a pair of CBS domains that strongly bind adenine nucleotides, thereby regulating enzyme activity. Eight residues associated with the CBS domains of mtCBS-PPase were screened to explore for possible associations with regulation of enzyme activity. The majority of substitutions (V99A, R168A, Y169A, Y169F, Y188A, and H189A) enhanced the catalytic activity of mtCBS-PPase, two substitutions (R170A and R187G) decreased activity, and one (K100G) had no effect. AMP-binding affinity was markedly decreased in the V99A, R168A, Y169A, and elevated in the R187G and H189A mutant proteins. Remarkably, the R168A and Y169A substitutions changed the effect of AMP from inhibition to activation. The stoichiometry of AMP binding increased from one t... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4158232 Thu, 11 Nov 2010 00:00:00 +0100 4158232 http://www.medworm.com/index.php?rid=4132306&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101391 Amyloid β-protein (Aβ[1]) is believed to cause Alzheimer’s disease (AD). Aβ42 is substantially more neurotoxic than Aβ40 and this increased toxicity correlates with existence of unique Aβ42 oligomers. Met35 oxidation to sulfoxide or sulfone eliminates the differences in early oligomerization between Aβ40 and Aβ42. Met35 oxidation to sulfoxide was reported to decrease Aβ assembly kinetics and neurotoxicity whereas oxidation to sulfone rarely has been studied. Based on these data, we expected that oxidation of Aβ to sulfone also would decrease its toxicity and assembly kinetics. To test this hypothesis, we compared systematically the effect of the wild-type, sulfoxide, and sulfone forms of Aβ40 and Aβ42 on ne... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4132306 Tue, 02 Nov 2010 00:00:00 +0100 4132306 http://www.medworm.com/index.php?rid=4132305&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101141 PKD2 is one of the two genes mutated in autosomal-dominant polycystic kidney disease (ADPKD). The protein product of PKD2, polycystin-2, functions as a non-selective cation channel in the endoplasmic reticulum and possibly at the plasma membrane. Hydrophobicity plots and its assignment to the TRP family of cation channels suggest that polycystin-2 contains 6 transmembrane domains and that both the NH2- and COOH-termini extend into the cytoplasm. However, no experimental evidence for this model has been provided so far. To determine the orientation of the different loops of polycystin-2, we truncated polycystin-2 within the predicted loops 1 to 5 and tagged the constructs at the COOH-terminus with a HA-epitope. After transient expression and selective membrane permeabilization, immunofluore... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4132305 Tue, 02 Nov 2010 00:00:00 +0100 4132305 http://www.medworm.com/index.php?rid=4116851&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101310 In this study, for the first time, we dissected the molecular mechanisms of VAMP-2 recognition by BoNT serotype F. The initial substrate recognition was mediated through sequential binding of VAMP-2 to the B1, B2, and B3 pockets in LC/F, which directed VAMP-2 to the active site of LC/F and stabilized the AS substrate recognition, where the P2, P1’ and P2’ sites of VAMP-2 were specifically recognized by the S2, S1’ and S2’ pockets of LC/F to promote the substrate hydrolysis. The understanding of the molecular mechanisms of LC/F substrate recognition provides insights into the development of antitoxins and engineering novel BoNTs to optimize current therapy and extend the therapeutic interventions. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=4116851 Thu, 28 Oct 2010 23:00:00 +0100 4116851 http://www.medworm.com/index.php?rid=4076596&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101293 This study provides a novel insight into molecular mechanisms by which SIRT1 regulates UPR signaling. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=4076596 Sun, 17 Oct 2010 23:00:00 +0100 4076596 http://www.medworm.com/index.php?rid=4072823&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101228 Decarboxylated S-adenosylmethionine (dcAdoMet, S-adenosyl-1-(methylthio)-3-propylamine) is an essential intermediate in the synthesis of polyamines. Its content is normally very low amounting to less than 5% of that of S-adenosylmethionine itself. It was found that in mice lacking spermine synthase there was a large increase in dcAdoMet and that overexpression of spermine synthase reduced the amount of this nucleoside. There was also an increase in dcAdoMet in cells derived from patients with Snyder-Robinson syndrome, a rare X-linked recessive human disease caused by SMS gene mutations that greatly reduce the content of spermine synthase. These results suggest that there is an inverse relationship between the amount of spermine synthase protein and the content of dcAdoMet and raise the pos... BJ Disease journals http://www.medworm.com/rss/comments.php?id=4072823 Thu, 14 Oct 2010 23:00:00 +0100 4072823 http://www.medworm.com/index.php?rid=3975918&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100996 Ionizing radiation causes DNA damage and consequent apoptosis, mainly due to the production of hydroxyl radicals that follows radiolytic splitting of water. However, superoxide and hydrogen peroxide also form and induce oxidative stress with resulting lysosomal membrane permeabilization (LMP) arising from iron-catalyzed oxidative events. The latter will significantly contribute to radiation-induced cell death and its degree largely depends on the quantities of lysosomal redox-active iron present as a consequence of autophagy and endocytosis of iron-rich compounds. Therefore, radiation sensitivity might be depressed by lysosome-targeted iron-chelators. Here we show that cells in culture are significantly protected from ionizing radiation damage if initially exposed to the lipophilic iron-ch... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3975918 Wed, 15 Sep 2010 23:00:00 +0100 3975918 http://www.medworm.com/index.php?rid=3964853&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100414 Little is known regarding the role of hyperglycemia on histone H3 modifications and in turn altering expression of genes during the development of diabetes associated complications. Hence, we studied hyperinsulinemia/hyperglycemia induced epigenetic changes and alteration of Fbn-1 and Col3A1 gene expression. Insulin resistance and type 2 diabetes in male Sprague-Dawley rats was developed by the high fat diet (HFD) feeding and administering low dose of Streptozotocin (STZ). Hyperglycemia induces deacetylation and dephosphorylation of histone H3 in the heart and kidney of diabetic rats. Furthermore, mRNA expression of Fbn-1 and Col3A1 gene increased in kidney and decreased in heart under hyperglycemic/hyperinsulinemic conditions. Similar to mRNA expression chromatin immunoprecipitation also ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3964853 Sun, 12 Sep 2010 23:00:00 +0100 3964853 http://www.medworm.com/index.php?rid=3938010&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101116 DNA repair mechanisms enable cells to maintain their genetic information by protecting it from mutations that may cause malignant growth. Recent evidence suggests that specific DNA repair enzymes contain iron-sulphur-clusters (ISCs). The nuclear-encoded protein frataxin is essential for the mitochondrial biosynthesis of ISCs. Frataxin deficiency causes a neurodegenerative disorder named Friedreich’s Ataxia in humans. Various types of cancer occurring at young age are associated with this disease, and hence with frataxin deficiency. Mice carrying a hepatocyte-specific disruption of the frataxin gene develop multiple liver tumours for unresolved reasons. Here we show that frataxin deficiency in murine liver is associated with increased basal levels of oxidative DNA base damage. Accord... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3938010 Sun, 05 Sep 2010 23:00:00 +0100 3938010 http://www.medworm.com/index.php?rid=3928442&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100847 Chondroitin sulfate (CS) is a glycosaminoglycan species that is widely distributed in the extracellular matrix. To understand the physiological roles of enzymes involved in CS synthesis, we produced CS N-acetylgalactosaminyltransferase 1 (CSGalNAcT1)-null mice. CS production was reduced by approximately half in CSGalNAcT1-null mice, and the amount of short-chain CS was also reduced. Moreover, the cartilage of the null mice was significantly smaller than that of wild-type. Additionally, type-II collagen fibers in developing cartilage were abnormally aggregated and disarranged in the homozygous mutant mice. These results suggest that CSGalNAcT1 is required for normal CS production in developing cartilage. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=3928442 Wed, 01 Sep 2010 23:00:00 +0100 3928442 http://www.medworm.com/index.php?rid=3898768&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100434 Misfolding of the islet β-cell peptide human amylin (hA) into β-sheet-containing oligomers is linked to β-cell apoptosis and the pathogenesis of type 2 diabetes. Here we investigated possible effects on hA misfolding of the chaperones HSP70, GRP78/BiP and HSP40/DnaJ, which co-localize with hA in organelles. We demonstrated that hA underwent spontaneous time-dependent β-sheet formation and aggregation by thioflavin-T fluorescence in solution, whereas mouse/rat amylin (rA) did not. HSP70, GRP78/BiP and HSP40/DnaJ each independently suppressed hA misfolding. Maximal molar protein:hA ratios at which chaperone activity was detected were 1:200 (HSP70, HSP40/DnaJ, GRP78/BiP). By contrast, none of the chaperones modified the secondary structure of rA. Human amylin, but ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3898768 Mon, 23 Aug 2010 23:00:00 +0100 3898768 http://www.medworm.com/index.php?rid=3861333&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100668 This study yields important mechanistic insight into how TMPRSS6 is activated. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=3861333 Wed, 11 Aug 2010 23:00:00 +0100 3861333 http://www.medworm.com/index.php?rid=3861332&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20101042 The extraordinary high toxicity of botulinum neurotoxins primarily results from their specific binding and uptake into neurons. At motor neurons, the seven botulinum neurotoxin serotypes A-G (BoNT/A-G) inhibit acetylcholine release leading to flaccid paralysis. Uptake of BoNT/A, B, E, F and G requires a dual interaction with gangliosides and the synaptic vesicle proteins synaptotagmin or SV2, whereas little is known about the cell entry mechanisms of the serotypes C and D that display the lowest amino acid sequence identity compared to the other five serotypes. Here, we demonstrate that the neurotoxicity of BoNT/D depends on the presence of gangliosides by employing phrenic nerve hemidiaphragm preparations derived from mice expressing GM3, GM2, GM1 and GD1a or only GM3. High resolution cry... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3861332 Wed, 11 Aug 2010 23:00:00 +0100 3861332 http://www.medworm.com/index.php?rid=3853727&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100581 A central role for mitochondrial dysfunctions has been proposed in the pathogenesis of Down syndrome (DS), a multifactorial disorder caused by trisomy of human chromosome 21. To explore whether and how abnormalities in mitochondrial energy metabolism are involved in DS pathogenesis, we investigated the catalytic properties, gene expression and protein levels of certain proteins involved in mitochondrial ATP synthesis such as ATPase, ADP/ATP translocator (ANT) and adenylate kinase (AK) in human skin fibroblasts from subjects with DS (DS-HSF) comparing them with euploid fibroblasts. In DS-HSF, we found a strong impairment of mitochondrial ATP synthesis due to a reduction in the catalytic efficiency of each of the investigated proteins. This impairment occurred in spite of unchanged gene ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3853727 Mon, 09 Aug 2010 23:00:00 +0100 3853727 http://www.medworm.com/index.php?rid=3805330&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100698 In this study, we investigated the role of dendritic cells (DCs) in the spreading of prion infection to neuronal cells. First, we determined that bone-marrow derived dendritic cells (BMDCs) rapidly uptake PrPSc after exposure to infected brain homogenate. Next, we observed a progressive catabolism of the internalized prion aggregates. Similar experiments performed with BMDCs isolated from knock-out (KO) or mice over-expressing PrP (tga20) indicate that both PrPSc uptake and catabolism are independent of PrPc expression in these cells. Finally, using co-cultures of prion-loaded BMDCs and cerebellar neurons, we characterized the transfer of the prion protein and the resulting infection of the neuronal cultures. Interestingly, the transfer of PrPSc was triggered by direct cell-to-cell contact... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3805330 Thu, 29 Jul 2010 23:00:00 +0100 3805330 http://www.medworm.com/index.php?rid=3783673&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100779 Distribution of selenium (Se) within the mammalian body is mediated by selenoprotein P (SePP), a Se-rich glycoprotein secreted by hepatocytes. Genetic and biochemical evidence indicate that the endocytic receptors ApoER2 and megalin mediate tissue-specific SePP uptake. Megalin-mutant mice were fed diets containing adequate (0.15 ppm) or low (0.08 ppm) Se content and were analyzed for tissue and plasma Se levels, cellular glutathione peroxidase (GPx) activities, and protein expression patterns. Megalin-mutant mice display increased urinary Se loss, which correlates with SePP excretion in their urine. Accordingly, serum Se and SePP are significantly reduced in megalin-mutant mice reaching marginal levels on the low Se diet. Moreover, kidney Se content and expression of renal selenoproteins a... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3783673 Thu, 22 Jul 2010 23:00:00 +0100 3783673 http://www.medworm.com/index.php?rid=3771513&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100725 We have previously reported that reactive site mutants of the N-terminal inhibitory domain of TIMP-3 (N-TIMP-3) modified at the N-terminus, selectively inhibited ADAM17 (A Disintegrin and Metalloprotease) over the MMPs (Matrix Metalloproteases). The primary aggrecanases, ADAMTS-4 and ADAMTS-5 (ADAM with Thrombospondin motifs) are ADAM17-related metalloproteases which are similarly inhibited by TIMP-3, but are poorly inhibited by other TIMPs. Using a newly developed recombinant protein substrate based on the interglobular domain (IGD) of aggrecan, gst-IGD-flag, these reactive site mutants were found to similarly inhibit ADAMTS-4 and ADAMTS-5. Further mutations of N-TIMP-3 indicated that up to two extra Ala residues can be attached to the N-terminus before the Ki(app) for A... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3771513 Mon, 19 Jul 2010 23:00:00 +0100 3771513 http://www.medworm.com/index.php?rid=3757175&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100627 Insulin, a 51-residue peptide hormone is an intrinsically amyloidogenic peptide, forming amyloid fibrils in vitro. In the secretory granules insulin is densely packed together with Zn(II) into crystals of Zn2Insulin6 hexamer, which assures osmotic stability of vesicles and prevents fibrillization of the peptide. However, after release from the pancreatic β-cells insulin dissociates into active monomers, which tend to fibrillize not only at acidic but also at physiological pH values. The effect of co-secreted Zn(II) ions on the fibrillization of monomeric insulin is unknown, however, it might prevent insulin fibrillization. We showed that Zn(II) inhibits fibrillization of monomeric insulin at physiological pH values by forming a soluble Zn(II)Insulin complex. Inhibitory effect of Zn(... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3757175 Wed, 14 Jul 2010 23:00:00 +0100 3757175 http://www.medworm.com/index.php?rid=3717860&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100425 The c-Jun N-terminal kinases (JNKs) are stress-activated serine/threonine kinases that can regulate both cell death and cell proliferation. We have developed a cell system to control JNK re-expression at physiological levels in JNK1/2-null murine embryonic fibroblasts (MEFs). JNK re-expression restored basal and stress-activated phosphorylation of the c-Jun transcription factor and attenuated cellular proliferation with increased cells in G1/S phase of the cell cycle. To explore JNK actions to regulate cell proliferation, we evaluated a role for the cytosolic protein, stathmin (STMN)/oncoprotein 18 (Op18). STMN, upregulated in a range of cancer types, plays a crucial role in the control of cell division through its regulation of microtubule dynamics of the mitotic spindle. In JNK1/2-null o... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3717860 Wed, 30 Jun 2010 23:00:00 +0100 3717860 http://www.medworm.com/index.php?rid=3647846&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100082 In this study it is shown that HOSCN targets Cys residues present in protein tyrosine phosphatases (PTPs) with this resulting in a loss of PTP activity for the isolated enzyme, in cell lysates and intact J774A.1 macrophage-like cells. Inhibition also occurs with MPO-generated HOCl and HOBr, but is more marked with MPO-generated HOSCN, particularly at longer incubation times. This inhibition is reversed by dithiothreitol, particularly at early time points, consistent with the reversible oxidation of the active site Cys residue to give either a Cys-SCN adduct or a sulfenic acid. Inhibition of PTP activity is associated with increased phosphorylation of p38α and ERK2 as detected by Western blotting and phosphoprotein arrays, and results in altered MAPK signalling. These data indicate t... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3647846 Tue, 08 Jun 2010 23:00:00 +0100 3647846 http://www.medworm.com/index.php?rid=3624738&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100285 In this study we investigate whether there are differences in inflammatory and insulin signalling pathways in visceral adipose tissue (VAT) that could account for the metabolic differences exhibited by morbid obese individuals either insulin resistant (IR-MO) or paradoxically insulin sensitive (NIR-MO). Our results indicate that there are pathways common to obesity and unrelated to insulin resistance and others that are discriminative for insulin resistance for a similar degree of obesity. For instance all MO patients, irrespectively of their insulin resistance, showed increased expression of TNF-α and activation of JNK1/2. However the IR-MO group showed significantly elevated expression levels of IL-1β and IL-6 and increased macrophage infiltrates compared with non obese ind... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3624738 Wed, 02 Jun 2010 23:00:00 +0100 3624738 http://www.medworm.com/index.php?rid=3617389&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091960 This study resulted in several important conclusions: (i) decreased NAD- and FAD-linked oxygen uptake rates and uncoupling between electron transport and synthesis of ATP were observed in fibroblasts from premutation carriers; (ii) a lower expression of mitochondrial proteins preceded both in age and in CGG repeats the appearance of overt clinical involvement; (iii) the CGG repeat size required for altered mitochondrial protein expression was also lower than that required to produce brain intranuclear inclusions from individuals who died with the premutation, suggesting that MD is an incipient pathological process occurring in individuals who do not display overt features of FXTAS; (iv) based on the CGG repeats, MD preceded the increase in oxidative/nitrative stress damage indicating that ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3617389 Mon, 31 May 2010 23:00:00 +0100 3617389 http://www.medworm.com/index.php?rid=3572984&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100330 Fetuin-A, a hepatic secretory protein, has recently been implicated in insulin resistance and type 2 diabetes. It is an endogenous inhibitor of insulin receptor tyrosine kinase. However, regulation of fetuin-A synthesis in relation to insulin resistance is yet unclear. Here we report that both free fatty acids and fetuin-A coexisted at high levels in the serum of db/db mice indicating a relationship between them. To study this in-depth, we selected HepG2 cells and rat primary hepatocytes, incubation of palmitate with them enhanced fetuin-A secretion to more than 4-fold over the control. Interestingly, cell lysates from these incubations showed overexpression and activity of NF-kB. In NF-kB knock out HepG2 cells, palmitate failed to increase fetuin-A secretion, whereas forced expression of ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3572984 Mon, 17 May 2010 23:00:00 +0100 3572984 http://www.medworm.com/index.php?rid=3563263&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100231 AMP-activated protein kinase (AMPK) signalling plays a key role in whole-body energy homeostasis although its precise role in pancreatic ß-cell function remains unclear. We therefore investigated whether AMPK plays a critical function in ß-cell glucose sensing and is required for the maintenance of normal glucose homeostasis. Mice lacking AMPKa2 in ß-cells and a population of hypothalamic neurons (RIPCrea2KO mice) and RIPCrea2KO mice lacking AMPKa1 globally were assessed for whole body glucose homeostasis and insulin secretion. Isolated pancreatic islets from these mice were assessed for glucose stimulated insulin secretion and gene expression changes. Cultured ß-cells were examined electrophysiologically for their electrical responsiveness to hypoglycaemia. RIP... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3563263 Wed, 12 May 2010 23:00:00 +0100 3563263 http://www.medworm.com/index.php?rid=3555443&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100373 In this study, we have uncovered further complexity involving the influence of multiple promoters and cross-talk between 5’ and 3’UTRs. We demonstrate that full-length ERβ messages are transcribed from three separate promoters; two promoters are well-established within the literature while the third represents a novel finding. Each promoter produces transcripts with distinct 5’UTRs. The differential 3’ splicing that produces transcripts coding for the ERβ isoforms also defines isoform-specific 3’UTRs. We identified exact 3’UTR sequences for each isoform, and show that alternative polyadenylation sites are used in a cell-type specific manner to produce transcripts with 3’UTRs of different lengths. Critically, we show that 5... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3555443 Tue, 11 May 2010 23:00:00 +0100 3555443 http://www.medworm.com/index.php?rid=3533123&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100360 Acidic proteins were isolated from synovial fluid from two osteoarthritic and two rheumatoid arthritic patients and identified by mass spectrometry. It was found that the most abundant protein in all the samples was the mucin-like protein lubricin. Further characterization of lubricin from the different patients by liquid chromatography-mass spectrometry of released oligosaccharides showed that the core 1 O-linked oligosaccharides NeuAcα2-3Galβ1-3GalNAc and NeuAcα2-3Galβ1-3(NeuAcα2-6)GalNAc were the dominating structures on lubricin. The latter was found to be more prevalent in the rheumatoid arthritis samples, indicating that sialylation is up-regulated as part of the inflammatory response. In addition to these dominating structures, core 2 structures we... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3533123 Tue, 04 May 2010 23:00:00 +0100 3533123 http://www.medworm.com/index.php?rid=3522254&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100223 A novel function of COMMD1 [copper (Cu) metabolism gene MURR1 (mouse U2af1-rs1 region 1) domain], a protein relevant to canine Cu toxicosis, was examined in the mouse hepatoma cell line Hepa 1-6 with multi-disciplinal techniques consisting of molecular and cellular biological techniques, elemental speciation and elemental imaging. To clarify the function of COMMD1, COMMD1 knockdown was accomplished by introducing siRNA into the cells. Although COMMD1 knockdown did not affect Cu incorporation, it inhibited Cu excretion, resulting in Cu accumulation. Cu accumulating in the cells predominantly existed in the form bound to metallothionein (MT). It is known that Atp7b, an ATP-dependent Cu transporter in liver, localizes on trans-Golgi network membrane under basal Cu condition and translocates t... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3522254 Thu, 29 Apr 2010 23:00:00 +0100 3522254 http://www.medworm.com/index.php?rid=3453054&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091667 Renal maturation occurs postnatally in many species and reabsorption capacity at birth can vary substantially from the mature kidney. However, little is known regarding the maturation of amino acid transport mechanisms, despite the well-known physiological state of developmental iminoglycinuria. Commonly seen during early infancy, developmental iminoglycinuria is a transient version of the persistent inherited form of the disorder, referred to as iminoglycinuria, and manifests as a urinary hyperexcretion of proline, hydroxyproline and glycine. The transporters involved in developmental iminoglycinuria and their involvement in the improvement of renal reabsorption capacity remain unknown. Quantitative RT-PCR (qPCR) and Western blot analysis in developing mouse kidney revealed that the expre... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3453054 Thu, 08 Apr 2010 23:00:00 +0100 3453054 http://www.medworm.com/index.php?rid=3453053&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100101 Heparan sulfate (HS) is synthesized by HS co-polymerases encoded by the EXT1 and EXT2 genes, which are known as causative genes for hereditary multiple exostoses, a dominantly inherited genetic disorder characterized by multiple cartilaginous tumors. It has been thought that the heterooligomeric EXT1-EXT2 complex is the biologically relevant form of polymerase and that targeted deletion of either EXT1 or EXT2 leads to a complete lack of HS synthesis. Here we show, unexpectedly, that two distinct cell lines defective in EXT1 expression indeed produce small but significant amounts of HS chains. The HS chains produced without the aid of EXT1 decreased in length compared with HS chains formed in concert with EXT1 and EXT2. In addition, biosynthesis of HS in EXT1-defective cells was notably blo... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3453053 Thu, 08 Apr 2010 23:00:00 +0100 3453053 http://www.medworm.com/index.php?rid=3440294&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100128 Classical late neuronal ceroid lipofuscinosis (LINCL) is a fatal neurodegenerative disease of children caused by mutations in TPP1, the gene encoding the lysosomal protease tripeptidyl peptidase 1. LINCL is characterized by lysosomal accumulation of storage material of which only a single protein component, subunit c of mitochondrial ATP synthase, has been well established to date. Identification of other protein constituents of the storage material could provide useful insights into the pathophysiology of disease and the natural substrates for TPP1. We have therefore initiated a proteomic analysis of storage material in brain from a LINCL mouse model. One protein, glial fibrillary acidic protein (GFAP), was found to be elevated in the LINCL mice compared to normal controls in both isolate... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3440294 Mon, 05 Apr 2010 23:00:00 +0100 3440294 http://www.medworm.com/index.php?rid=3440293&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091868 Selenium modifies inflammatory reactions in rodents and humans. The liver controls metabolism and transport of selenium via hepatically-derived selenoprotein P (SEPP). Intracellular selenoprotein S (SEPS) modifies endoplasmic reticulum function and immune cell activity. Polymorphisms in SEPS were associated with cytokine levels and inflammatory diseases in a subset of clinical studies. We hypothesized that sex and selenium represent decisive parameters controlling immune response and regulation of SEPS expression in vivo. Male and female mice on Se-poor diet were supplemented or not with selenite for three days and injected with saline or LPS 24 h before analysis. Selenium supplementation mitigated the LPS-induced rise in circulating cytokines in male mice. Serum SepP and selenium concentr... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3440293 Mon, 05 Apr 2010 23:00:00 +0100 3440293 http://www.medworm.com/index.php?rid=3424089&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091880 Plasmodium falciparum is the causative agent of malaria, a disease where new drug targets are required due to increasing resistance to current anti-malarials. Thymidylate kinase (TMPK) is a good candidate since it is essential for the synthesis of dTTP, a critical precursor of DNA and has been much studied due to its role in prodrug activation and as a drug target. Type I TMPKs such as the human enzyme, phosphorylate the substrate 3'-azido-3'-deoxythymidine monophosphate (AZTMP) inefficiently compared to type II TMPKs (e.g. E. coli TMPK). Here we report that eukaryotic P. falciparum TMPK presents sequence features of a type I enzyme yet kinetic parameters for AZTMP phosphorylation are similar to those of the highly efficient E. coli enzyme. Structural information shows that this is explain... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3424089 Mon, 29 Mar 2010 23:00:00 +0100 3424089 http://www.medworm.com/index.php?rid=3407696&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091091 During mammary gland involution different signals are required for apoptosis and tissue remodeling. To explore the role of NO in the involution of mammary tissue after lactation, NOS-2-/- mice were used. No apparent differences were observed between NOS-2-/- and WT animals during pregnancy and lactation. However, upon cessation of lactation a notable delay in involution was observed, compared to WT mice. KO mice showed increased phosphorylation of STAT5 during weaning, concomitant with increased beta-casein mRNA levels when compared to weaned WT glands, both hallmarks of the lactating period. In contrast, activation of STAT3, although maximal at 24h weaning, was significantly reduced in NOS-2-/- mice. STAT3 and NFkappaB signaling pathways are known to be crucial in the regulation of cell d... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3407696 Fri, 26 Mar 2010 00:00:00 +0100 3407696 http://www.medworm.com/index.php?rid=3403178&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100232 We describe serotype specific patterns of GBS Sia O-acetylation that can be manipulated by genetic and biochemical means. In vitro and in vivo assays demonstrate this subtle modification attenuates GBS Sia-mediated neutrophil suppression and animal virulence. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=3403178 Thu, 25 Mar 2010 00:00:00 +0100 3403178 http://www.medworm.com/index.php?rid=3403177&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091635 Prions diseases are fatal, transmissible, neurodegenerative diseases that result from structural conversion of the prion protein to a disease associated isoform. The prion protein contains a single disulfide bond. Our analysis of all NMR structures of the prion protein (total of 440 structures over 9 species) containing an explicit disulfide bond reveals that the bond exists predominantly in a stable, low-energy state but can also adopt a high-energy configuration. The sidechains of two tyrosine residues and one phenylalanine residue control access of solvent to the disulfide bond. Notably, the sidechains rotate away from the disulfide bond in the high energy state, exposing the disulfide bond to solvent. The importance of these aromatic residues for protein function was analysed by mutati... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3403177 Thu, 25 Mar 2010 00:00:00 +0100 3403177 http://www.medworm.com/index.php?rid=3349672&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100016 Previous studies showed that apolipoprotein E (apoE) expression in macrophages suppresses inflammatory response. Whether the endogenously synthesized apoE acts intracellularly or after its secretion in suppressing macrophage inflammation remains unclear. The current study used the murine macrophage cell line RAW 264.7 to examine the influence of exogenous apoE on macrophage inflammatory responses induced by toll-like receptor (TLR)-4 and TLR-3 agonists lipopolysaccharide (LPS) and poly(I-C), respectively. Results showed that exogenously added apoE suppressed LPS- and poly(I-C)-induction of interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α secretion by RAW 264.7 cells. The mechanism was related to apoE suppression of TLR agonist-induced phosphorylation of c-Jun N-te... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3349672 Wed, 10 Mar 2010 00:00:00 +0100 3349672 http://www.medworm.com/index.php?rid=3330726&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091177 In conclusion, Cdx2 reduced Shh expression by binding to the unmethylated Shh promoter in the intestinal metaplastic mucosa of Cdx2-transgenic mouse stomach. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=3330726 Thu, 04 Mar 2010 00:00:00 +0100 3330726 http://www.medworm.com/index.php?rid=3310800&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091607 Phosphatidylglycerol is a widely used mimetic to study the effects of antimicrobial peptides (AMPs) on the bacterial cytoplasmic membrane. It turned out, however, that the antibacterial activities of novel NK-2-derived AMPs could not sufficiently explained by using this simple model system. Since the lipopolysaccharide (LPS) containing outer membrane is the first barrier of Gram-negative bacteria, here we investigated interactions of NK-2 and a shortened variant thereof with viable Escherichia coli WBB01 and Proteus mirabilis R45, and with model membranes composed of LPS isolated from these two strains. Differences in net charge and charge distribution of the two LPS have been made responsible for the differential sensitivity of the respective bacteria to other AMPs. As imaged by TEM and A... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3310800 Fri, 26 Feb 2010 00:00:00 +0100 3310800 http://www.medworm.com/index.php?rid=3275322&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100074 There is a need to develop inhibitors of mosquito-borne flaviviruses, including West Nile virus (WNV). Here, we describe a novel and efficient recombinant antibody technology that led us to the isolation of the inhibitory, high affinity, human antibodies to the active site region of a viral proteinase. As a proof-of-principal, we have successfully used this technology and the synthetic naive human antibody library HuCAL GOLD to isolate selective and potent function-blocking, active site-targeting antibodies to the two-component WNV NS2B-NS3 serine proteinase, the only proteinase encoded by the flaviviral genome. First, we used the wild-type enzyme in the antibody screens. The positive antibody clones were next counter-screened using the NS2B-NS3 mutant with a single mutation of the catalyt... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3275322 Tue, 16 Feb 2010 00:00:00 +0100 3275322 http://www.medworm.com/index.php?rid=3258182&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20100043 In conclusion, electrostatic interaction between ExoS and 14-3-3 via polar residues (S416, H418, D424 and D427) appears to be of secondary importance. Thus, the interaction between the “roof” of the groove of 14-3-3 and ExoS relies more on hydrophobic interaction forces, which probably contributes to induce cell death after ExoS infection and activation. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=3258182 Tue, 09 Feb 2010 00:00:00 +0100 3258182 http://www.medworm.com/index.php?rid=3219775&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091888 To assess the potential of mutations from the L1 loop of the tumour suppressor p53 as second-site suppressors, the effect of H115N and S116M on the p53 “hot spot” mutations has been investigated using the double mutant approach. The effects of these two mutants on the p53 “hot spots” in terms of thermal stability and DNA binding were evaluated. The results show that: (1) mutants H115N and S116M are thermally more stable than wild-type p53; (2) H115N but not S116M is capable of rescuing the DNA binding of one of the most frequent p53 mutants in cancer, R248Q, as shown by binding of R248Q/H115N to gadd45; (3) the double mutant R248Q/H115N is more stable than wild-type p53; (4) the effect of H115N as a second-site suppressor to restore DNA-binding activity is speci... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3219775 Fri, 29 Jan 2010 00:00:00 +0100 3219775 http://www.medworm.com/index.php?rid=3188535&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091097 In this report, we demonstrated that vimentin is a primary receptor required for IbeA+ E. coli K1-induced signaling and invasion of HBMEC, based on the following observations. First, E44 (IbeA+ E. coli K1 strain) invasion was blocked by vimentin inhibitors (Withfferin A and Acrylamide), a recombinant protein containing vimentin head domain and an antibody against the head domain, respectively. Secondly, overexpression of GFP-vimentin and GFP-vimentin head domain deletion mutant (VDM) significantly increased and decreased bacterial invasion, respectively. Thirdly, bacterial invasion was positively correlated with phosphorylation of vimentin at serine 82 by calcium calmodulin-dependent kinase II (CaM kinase II) and IbeA+ E. coli-induced phosphorylation of extracellular r... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3188535 Wed, 20 Jan 2010 00:00:00 +0100 3188535 http://www.medworm.com/index.php?rid=3114430&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091570 Down-regulation of the catalytic subunit of the mitochondrial H+-ATP synthase (β-F1-ATPase) is a hallmark of many human tumors. The expression level of β-F1-ATPase provides a marker of the prognosis of cancer patients as well as of the tumor response to chemotherapy. However, the mechanisms that participate in down-regulating its expression in human tumors remain unknown. Herein, we have studied the expression of β-F1-ATPase mRNA (β-mRNA) in breast, colon and lung adenocarcinomas and squamous carcinomas of the lung. Despite the down-regulation of the protein, tumor β-mRNA levels remained either unchanged (breast and lung adenocarcinomas) or significantly increased (colon and squamous lung carcinomas) when compared to paired normal tissues, suggesti... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3114430 Wed, 23 Dec 2009 00:00:00 +0100 3114430 http://www.medworm.com/index.php?rid=3114429&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091351 Legionnaires' disease is caused by a lethal colonization of alveolar macrophages with the Gram negative bacterium Legionella pneumophila. An L. pneumophila glucosyltransferase (LpGT or Lgt1) has recently been identified as a virulence factor, shutting down protein synthesis in the human cell by specific glucosylation of elongation factor 1A (EF1A), using an unknown mode of substrate recognition, and retaining glycosyl transfer. We have determined the crystal structure of LpGT in complex with substrates, revealing a GT-A fold with two unusual protruding domains. Through structure-guided mutagenesis of LpGT, several residues essential for binding of the UDP-glucose donor and EF1A acceptor substrates were identified, also affecting L. pneumophila virulence as demonstrated by microinjection st... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3114429 Wed, 23 Dec 2009 00:00:00 +0100 3114429 http://www.medworm.com/index.php?rid=3084332&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091612 We report that frataxin iron binding capacity is quite robust: even when five of the most conserved residues from the putative iron binding region are altered, at least 2 iron atoms per monomer can be bound, although with decreased affinity. Furthermore, we conclude that the acidic ridge is designed to favour function over stability. The negative charges have a functional role, but at the same time significantly impair frataxin’s stability. Removing five of those charges results in a thermal stabilization of ~24ºC and reduces the inherent conformational plasticity. Alterations on the conserved β-sheet residues have only a modest impact on the protein stability, highlighting the functional importance of residues 122-124. (Source: BJ Disease) BJ Disease journals http://www.medworm.com/rss/comments.php?id=3084332 Mon, 14 Dec 2009 00:00:00 +0100 3084332 http://www.medworm.com/index.php?rid=3007417&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091413 Oncogenic Ras mutations render the protein constitutively active and promote tumourigenisis via chronic stimulation of effector pathways. In A549 lung adenocarcinoma approximately 50% of the total Ras population is constitutively active yet these cells display only weak activation of the effectors: ERK1/2 and Akt. In order to identify key negative regulators of oncogenic Ras signalling we performed a phosphatome RNAi screen in A549 cells and ranked their effects on phosphorylation of Ser473 of Akt. As expected, the tumour suppressor PTEN emerged as a leading hit – knockdown elevated Akt activation to 70% of maximal generated by acute EGF stimulation. Importantly, we identified other phosphatases with similar potencies including PTPN2 (TC-PTP) and PTPRJ (DEP-1/CD148). Potentiation of... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3007417 Thu, 19 Nov 2009 00:00:00 +0100 3007417 http://www.medworm.com/index.php?rid=3007416&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091062 The activity of the pro-inflammatory cytokine IL-1 is closely regulated in vivo via a variety of mechanisms, including both the control of IL-1 production and secretion as well as naturally occurring inhibitors of IL-1 function such as IL-1ra. IL-1ra is homologous to IL-1, and is able to bind but not activate the IL-1 receptor. IL-1ra can be produced by a variety of cell types, and its production is stimulated by inflammatory signals. Here we show that in macrophages the TLR mediated induction of IL-1ra from both its proximal and distal promoters involves the p38 and ERK1/2 MAPK cascades. In addition we show that mitogen and stress activated kinase 1 (MSK1) and 2, kinases activated by either ERK1/2 or p38 in vivo, are required for the induction of both IL-1ra mRNA and protein. MSKs regulat... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3007416 Thu, 19 Nov 2009 00:00:00 +0100 3007416 http://www.medworm.com/index.php?rid=3007415&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090813 Cystic Fibrosis (CF) mostly follows a single F508 deletion in CFTR (ΔF508), thereby causing premature fragmentation of the nascent protein with concomitant alterations of diverse cellular functions. We show that CK2, the most pleiotropic protein kinase, undergoes allosteric control of its different cellular forms in the presence of short CFTR peptides encompassing the F508 deletion: these ΔF508 peptides drastically inhibit the isolated catalytic subunit (α) of the kinase and yet up-regulate the holoenzyme, composed of two catalytic and two non catalytic (β) subunits. Remarkable agreement between in silico docking and our biochemical data point to different sites for CFTR-ΔF peptide binding on isolated CK2α and on CK2β assembled into the holo... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3007415 Thu, 19 Nov 2009 00:00:00 +0100 3007415 http://www.medworm.com/index.php?rid=3003172&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090896 A putative guanidine diphosphomannose pyrophophosphorylase (GDP-Man PP) gene from Trypanosoma brucei was identified in the genome and subsequently cloned, sequenced, and recombinantly expressed and shown to be a catalytically active dimer. Kinetic analysis revealed a Vmax of 0.34 μmol / min/ mg and Km’s of 67 μM and 12 μM for GTP and mannose-1-phosphate respectively. Further kinetic studies showed GDP-Man was a potent product feedback inhibitor. RNAi of the cytosolic TbGDP-Man PP showed mRNA levels were reduced to ~20% of wild type levels, causing the cells to die after 3-4 days, demonstrating TbGDP-Man PP is essential in the bloodstream form of T.brucei and thus a potential drug target. The RNAi induced parasites have a greatly reduced capability to form GDP-M... BJ Disease journals http://www.medworm.com/rss/comments.php?id=3003172 Wed, 18 Nov 2009 00:00:00 +0100 3003172 http://www.medworm.com/index.php?rid=2911765&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090045 Microsomal prostaglandin E synthase-1 (mPGES-1) is a stimulus-inducible enzyme that functions downstream of cyclooxygenase (COX)-2 in the prostaglandin E2 (PGE2)-biosynthetic pathway. Although COX-2-derived PGE2 is known to play a role in the development of various tumours, the involvement of mPGES-1 in carcinogenesis has not yet been fully understood. Here, we used Lewis lung carcinoma (LLC) cells with mPGES-1 knockdown or overexpression as well as mPGES-1-deficient mice to examine the roles of cancer cell- and host-associated mPGES-1 in the processes of tumorigenesis in vitro and in vivo. We found that siRNA silencing of mPGES-1 in LLC cells decreased PGE2 synthesis markedly, accompanied by reduced cell proliferation, attenuated Matrigel invasiveness and increased extracellular matrix ad... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2911765 Tue, 20 Oct 2009 23:00:00 +0100 2911765 http://www.medworm.com/index.php?rid=2911764&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091119 The proliferation of the malaria-causing parasite Plasmodium falciparum within the erythrocyte is concomitant with massive phosphatidylcholine and phosphatidylethanolamine biosynthesis. Based on pharmacological and genetic data, de novo biosynthesis pathways of both phospholipids appear essential for parasite survival. The present study characterizes P. falciparum choline kinase (PfCK) and ethanolamine kinase (PfEK), which catalyse the first enzymatic steps of these essential metabolic pathways. Recombinant PfCK and PfEK were expressed as His-tagged fusion proteins from over-expressing E. coli strains, then purified to homogeneity and characterized. Using mice-polyclonal antibodies against recombinant kinases, PfCK and PfEK were shown to be localized within the parasite cytoplasm. Protein ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2911764 Tue, 20 Oct 2009 23:00:00 +0100 2911764 http://www.medworm.com/index.php?rid=2893798&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090776 In this study we show that serotonin is a favoured substrate for myeloperoxidase because other physiological substrates for this enzyme, including chloride, did not affect its rate of oxidation. At low micromolar concentrations, serotonin enhanced hypochlorous acid production by both purified myeloperoxidase and neutrophils. At higher concentrations it almost completely blocked formation of hypochlorous acid. Serotonin was oxidized to a dimer by myeloperoxidase and hydrogen peroxide. It was also converted to tryptamine-4,5-dione, especially in the presence of superoxide. This toxic quinone was produced by stimulated neutrophils in a reaction that required myeloperoxidase. In plasma, stimulated human neutrophils oxidized serotonin to its dimer using the NADPH oxidase and myeloperoxidase. We... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2893798 Tue, 13 Oct 2009 23:00:00 +0100 2893798 http://www.medworm.com/index.php?rid=2889850&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091213 In this study, we show that STAT3 binds the C-terminal tubulin associating region of SCLIP. In a search for a function of SCLIP we show that SCLIP was downregulated during OSM treatment in MCF-7 cells, which also stimulates epithelial morphology loss. SCLIP knockdown likewise triggered a loss of epithelial morphology which included reduced E-cadherin expression. We found that STAT3 was required to maintain SCLIP stability. Furthermore, inhibition of OSM-induced STAT3 activity preserved SCLIP expression and MCF-7 epithelial monolayers. Taken together, we propose that a STAT3/SCLIP interaction is required to preserved SCLIP stability and contributes to the maintenance of normal epithelial morphology. Disruption of STAT3/SCLIP interaction with OSM may contribute to cytokine mediated loss in c... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2889850 Tue, 13 Oct 2009 23:00:00 +0100 2889850 http://www.medworm.com/index.php?rid=2875139&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090343 The Gram-negative oral anaerobe Prevotella intermedia forms an iron(III) protoporphyrin IX pigment from haemoglobin. The microorganism expresses a 90 kDa cysteine protease, Interpain A (InpA), a homologue of Streptococcus pyogenes streptopain (SpeB). The role of InpA in haemoglobin breakdown and haem release was investigated. At pH 7.5, InpA mediated oxidation of oxyhaemoglobin to hydroxymethaemoglobin (in which the haem iron is oxidised to the Fe(III) state and which carries OH- as the sixth co-ordinate ligand) by limited proteolysis of globin chains as indicated by SDS-PAGE and MALDI-TOF analysis. Prolonged incubation at pH 7.5, did not result in further haemoglobin protein breakdown, but in the formation of a haemoglobin haemichrome (where the haem Fe atom is co-ordinated by another ami... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2875139 Thu, 08 Oct 2009 23:00:00 +0100 2875139 http://www.medworm.com/index.php?rid=2865099&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091024 The brain-specific compound N-acetylaspartate (NAA) occurs almost exclusively in neurons, where its concentration reaches ≈ 20 mM. Its abundance is determined in patients by magnetic resonance spectroscopy to assess neuronal density and health. The molecular identity of the N-acetyltransferase that catalyses NAA synthesis has remained unknown, because this enzyme is membrane-bound and difficult to purify. Database searches indicated that, among the putative N-acetyltransferases (i.e., proteins homologous to known N-acetyltransferases, but with uncharacterized catalytic activity) encoded by the human and mouse genomes, two, NAT8L and NAT14, were almost exclusively expressed in brain. Transfection studies in HEK293T cells indicated that NAT8L, but not NAT14, catalysed the synthesis of... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2865099 Mon, 05 Oct 2009 23:00:00 +0100 2865099 http://www.medworm.com/index.php?rid=2777782&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20091035 The Leucine Rich Repeat Protein Kinase-2 (LRRK2) is mutated in a significant number of Parkinson’s disease patients, but little is known about its regulation and function. A common mutation changing Gly2019 to Ser enhances catalytic activity, suggesting small molecule inhibitors might have utility in treating Parkinson’s Disease. We utilised various approaches to explore the substrate specificity requirements of LRRK2 and elaborated a peptide substrate termed Nictide, that had 20-fold lower Km and nearly 2-fold higher Vmax than the widely deployed LRRKtide substrate. We demonstrate that LRRK2 has marked preference for phosphorylating Thr over Ser. We also observed that several Rho kinase (ROCK) inhibitors such as Y-27632 and H-1152, suppressed LRRK2 with similar potency to wh... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2777782 Tue, 08 Sep 2009 23:00:00 +0100 2777782 http://www.medworm.com/index.php?rid=2740791&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090424 Hemochromatosis is an iron overload disorder with age-dependent oxidative stress and dysfunction in a variety of tissues. Mutations in HFE are responsible for most cases with hemochromatosis. We recently demonstrated that Hfe is expressed exclusively in the basal membrane of retinal pigment epithelium (RPE). Here we used Hfe-/- mice to examine ferritin levels (an indirect readout for iron levels) and morphological changes in retina. We found increased ferritin accumulation in retina in 18-month-old but not in 2-month-old mice with considerable morphological damage compared to age-matched controls. The retinal phenotype included hypertrophy and hyperplasia of RPE. RPE cells isolated from Hfe-/- mice exhibited a hyperproliferative phenotype. We also compared the gene expression profile betwe... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2740791 Thu, 27 Aug 2009 23:00:00 +0100 2740791 http://www.medworm.com/index.php?rid=2715376&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090664 MAC (Mitochondrial Apoptosis-induced Channel) forms in the mitochondrial outer membrane and unleashes cytochrome c, which then orchestrates the execution of the cell. MAC opening is the commitment step of intrinsic apoptosis. Hence, closure of MAC may prevent apoptosis. Compounds that blocked release of fluorescein from liposomes by recombinant Bax were tested for their ability to directly close MAC and suppress apoptosis in FL5.12 cells. Low doses of these compounds (IC50 ranged from 19 to 966 nM) irreversibly closed MAC. These compounds also blocked cytochrome c release and halted the onset of apoptotic markers normally induced by IL-3 deprivation or staurosporine. Our results reveal the tight link amongst MAC activity, cytochrome c release, and apoptotic death, and indicate this mitocho... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2715376 Wed, 19 Aug 2009 23:00:00 +0100 2715376 http://www.medworm.com/index.php?rid=2666768&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090541 Spondyloepiphyseal dysplasia tarda (SEDT) is a late-onset X-linked recessive skeletal dysplasia caused by mutations in the gene SEDL coding for sedlin. Here, we investigate four missense mutations observed in SEDT and compare biochemical and cellular characteristics relative to the wild-type protein to address mechanism of disease and to gain insight into the function of the sedlin protein. In situ hybridization and immunohistochemical experiments in mouse growth plates revealed sedlin to be predominantly expressed in proliferating and hypertrophic chondrocytes. Cell culture studies showed the wild-type protein localized predominantly in the vicinity of the nucleus and the Golgi with further localization around the cytoplasm, whilst mutation resulted in mislocalization. The D47Y mutation e... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2666768 Sun, 02 Aug 2009 23:00:00 +0100 2666768 http://www.medworm.com/index.php?rid=2633698&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090390 The hypothesis that PDHK4 has potential as a target for the treatment of type 2 diabetes was tested by feeding wild type and PDHK4 knockout mice a high saturated fat diet that induces hyperglycemia, hyperinsulinemia, glucose intolerance, hepatic steatosis, and obesity. Previous studies have shown that PDHK4 deficiency lowers blood glucose by limiting the supply of three carbon gluconeogenic substrates to the liver. There is concern, however, that the increase in glucose oxidation caused by less inhibition of the pyruvate dehydrogenase complex by phosphorylation will inhibit fatty acid oxidation, promote ectopic fat accumulation, and worsen insulin sensitivity. This was examined by feeding wild type and PDHK4 knockout mice a high saturated fat diet for 8 months. Fasting blood glucose levels... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2633698 Wed, 22 Jul 2009 23:00:00 +0100 2633698 http://www.medworm.com/index.php?rid=2579694&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090817 FtsZ plays an essential role in bacterial cell division. We have used the assembly of FtsZ as a screen to find antibacterial agents with a novel mechanism of action. The effects of 81 compounds of 29 different structural scaffolds on FtsZ assembly in vitro were examined using a sedimentation assay. Out of these 81 compounds, 3-{5-[4-Oxo-2-thioxo-3-(3-trifluoromethyl-phenyl)-thiazolidin-5-ylidenemethyl]-furan-2-yl}-benzoic acid (OTBA) was found to promote FtsZ assembly in vitro. OTBA increased the assembly of FtsZ, caused bundling of FtsZ protofilaments, prevented dilution-induced disassembly of FtsZ protofilaments and decreased the GTPase activity in vitro. It bound to FtsZ with an apparent dissociation constant of 15 ± 1.5 µM. Further, OTBA inhibited the proliferation of Bac... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2579694 Mon, 06 Jul 2009 23:00:00 +0100 2579694 http://www.medworm.com/index.php?rid=2575824&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20082398 The hereditary spastic paraplegias (HSPs) are genetic conditions exhibiting distal degeneration of the longest axons of the corticospinal tract, resulting in spastic paralysis of the legs. The gene encoding spartin is mutated in Troyer syndrome, an HSP in which paralysis is accompanied by additional clinical features. There has been controversy over the subcellular distribution of spartin. We show here that at steady state endogenous spartin exists in a cytosolic pool that can be recruited to endosomes and to lipid droplets. Cytosolic endogenous spartin is mono-ubiquitinated and we demonstrate that it interacts via a PPXY motif with the ubiquitin E3 ligases AIP4 (WWP2) and AIP5 (WWP1). Surprisingly, neither the PPXY motif, AIP4 nor AIP5 are required for spartin’s ubiquitination and ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2575824 Sun, 05 Jul 2009 23:00:00 +0100 2575824 http://www.medworm.com/index.php?rid=2569157&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090420 The pro-inflammatory chemokine CCL2 (MCP-1) is upregulated in the glomerular compartment during the early phase of LPS-induced nephritis. This upregulation also appears in cultured mesangial cells (MC) and is more pronounced in MC lacking the prostaglandin EP2 receptor or in MC treated with a prostaglandin EP4 receptor antagonist. To examine a possible feedback of EP receptor stimulation on CCL2 expression, we chose an in vitro model in MC with down regulated EP receptor expression. By selective overexpression of EP receptors in these cells, their effects on LPS-induced CCL2 expression were examined. Cells were stimulated with LPS and CCL2 gene expression was examined and compared to LPS stimulated, mock transfected COX-2+ cells. Overexpression of EP1 as well as EP3 had no effect o... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2569157 Wed, 01 Jul 2009 23:00:00 +0100 2569157 http://www.medworm.com/index.php?rid=2503404&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090278 Streptococcus pyogenes is one of the most common human pathogens and possesses diverse mechanisms to evade the human immune defence. One example of its immune evasion is the degradation of the chemokine IL-8 by ScpC, a serine proteinase that prevents the recruitment of neutrophils to an infection site. By applying the ANTIGENome technology and using human serum antibodies we identified Spy0416, annotated as ScpC, as a prominent antigen that induces protective immune responses in animals. We demonstrate here for the first time that the recombinant form of Spy0416 is capable of IL-8 degradation in vitro in a concentration and time dependent manner. Mutations in the conserved amino acid residues of the catalytic triad of Spy0416 completely abolished in vitro activity. However, the isolated pr... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2503404 Tue, 23 Jun 2009 23:00:00 +0100 2503404 http://www.medworm.com/index.php?rid=2503403&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090014 Receptor tyrosine kinases of the Eph family become tyrosine phosphorylated and initiate signaling events upon binding of their ligands, the ephrins. Eph receptors such as EphA2 and EphB4 are highly expressed but poorly tyrosine phosphorylated in many types of cancer cells, suggesting a limited interaction with ephrin ligands. Nevertheless, decreasing the expression of these receptors affects the malignant properties of cancer cells, suggesting that Eph receptors may influence cancer cells independently of ephrin stimulation. Ligand-independent activities of Eph receptors in cancer, however, have not been demonstrated. By using siRNA interference to downregulate EphB4 in MCF7 and MDA-MB-435 cancer cells, we found that EphB4 inhibits integrin-mediated cell substrate adhesion, spreading, and ... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2503403 Tue, 23 Jun 2009 23:00:00 +0100 2503403 http://www.medworm.com/index.php?rid=2503405&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090748 Primary hyperoxaluria type 1 (PH1) is a severe inborn disorder of glyoxylate metabolism, caused by a functional deficiency of the peroxisomal enzyme alanine:glyoxylate aminotransferase (AGXT), which converts glyoxylate to glycine using L-alanine as the amino-group donor. Even though pre-genomic studies indicate that other human transaminases can convert glyoxylate to glycine, in PH1 patients these enzymes are apparently unable to compensate for the lack of AGXT - perhaps due to their limited levels of expression, or to their localization in an inappropriate cell compartment, or to the scarcity of the required amino-group donor. Herein, we describe the cloning of eight human cytosolic aminotransferases, their recombinant expression as His6-tagged proteins and a comparative study on their ab... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2503405 Mon, 22 Jun 2009 23:00:00 +0100 2503405 http://www.medworm.com/index.php?rid=2467844&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090564 4-Hydroxynonenal (HNE), the major product of lipoperoxidation, easily reacts with proteins through adduct formation between its three main functional groups and lysyl, histidyl, and cysteinyl residues of proteins. HNE is considered to be an ultimate mediator of toxic effects elicited by oxidative stress. It can be detected in several patho-physiological conditions, in which it affects cellular processes by addition to functional proteins. We demonstrated by mass spectrometry and confirmed by immunoblotting experiments the formation of HNE-α-enolase adduct(s) in HL-60 human leukemic cells. α-Enolase is a multifunctional protein that acts as a glycolytic enzyme, transcription factor (c-myc binding protein, MBP-1) and plasminogen receptor. HNE did not affect α-enolase enz... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2467844 Tue, 09 Jun 2009 04:00:00 +0100 2467844 http://www.medworm.com/index.php?rid=2455845&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090276 This study shows for the first time that the reactions of HOSCN with low-molecular-mass thiol residues occur with rate constants in the range 7.3 × 103 M–1 s–1 (for N-acetyl-cysteine) at pH 7.4 to 7.7 × 106 M–1 s–1 (for 5-thio-2-nitrobenzoic acid at pH 6.0). An inverse relationship between the rate of reaction and the pKa of the thiol group was observed. The rates of reaction of HOSCN with thiol-containing proteins were also investigated for four proteins (creatine kinase, bovine serum albumin, β−lactoglobulin and crystallins). The values obtained for Cys residues on these proteins are in the range 1 – 7 × 104 M–1 s–1. These second-order rate constants indicate that HOSCN is a major mediator of thiol oxidat... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2455845 Wed, 03 Jun 2009 04:00:00 +0100 2455845 http://www.medworm.com/index.php?rid=2422659&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090530 The Slc30a8 gene encodes the islet-specific zinc transporter ZnT-8, which provides zinc for insulin-hexamer formation. Polymorphic variants in amino acid 325 of human ZnT-8 are associated with altered susceptibility to type 2 diabetes and ZnT-8 autoantibody epitope specificity changes in type 1 diabetes. To assess the physiological importance of ZnT-8, mice carrying a Slc30a8 exon 3 deletion were analyzed histologically and phenotyped for energy metabolism and pancreatic hormone secretion. No gross anatomical or behavioral changes or differences in body weight were observed between wild type and ZnT-8 -/- mice and ZnT-8 -/- mouse islets were indistinguishable from wild type in terms of their numbers, size and cellular composition. However, total zinc content was markedly reduced in ZnT-8 -... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2422659 Mon, 18 May 2009 04:00:00 +0100 2422659 http://www.medworm.com/index.php?rid=2413015&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090389 Dynasore, a small molecule inhibitor of dynamin, was used to probe the role of dynamin in the endocytosis of wild-type and mutant CFTR. Internalization of both wild-type and “temperature-corrected” ΔF508 CFTR was markedly inhibited by short exposure to dynasore, implicating dynamin as a key element in the endocytic internalization of both wild-type and mutant CFTR. The inhibitory effect of dynasore was readily reversible upon washout of dynasore from the growth media. Corr-4, a pharmacological corrector of ΔF508 CFTR biosynthesis, caused a marked increase in the cell surface expression of mutant CFTR. Co-incubation of ΔF508 CFTR expressing cells with corr-4 and dynasore caused a significantly greater level of cell surface CFTR than that observed in the pr... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2413015 Thu, 14 May 2009 04:00:00 +0100 2413015 http://www.medworm.com/index.php?rid=2363591&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20090356 We examined ROS production in astrocytes and downstream effects leading to changes in signaling cascade, morphology, and membrane dynamics using menadione, a redox active compound capable of inducing intracellular ROS. NADPH oxidase mediated menadione-induced ROS production, which then stimulated phosphorylation of p38 mitogen-activated protein kinase (MAPK) and extracellular-signal regulated kinases (ERK1/2), and increased actin polymerization and cytoskeletal protrusions. We also showed that astrocyte plasma membranes became more molecularly-ordered under oxidative stress, which was abrogated by down regulating cytosolic phospholipase A2 (cPLA2) either with a pharmacological inhibitor or by RNA interference. In addition, a mild disruption of F-actin with cytochalasin D suppressed menadio... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2363591 Fri, 24 Apr 2009 04:00:00 +0100 2363591 http://www.medworm.com/index.php?rid=2346642&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20081466 Numerous studies conducted in a diversity of adult tissues have reported that certain stem cells are characterized by the expression of a protein known as the ABCG2 transporter. In the adult pancreas, various multipotent progenitors have been proposed, however the ABCG2 marker has only been detected in the so-called Side Population. In the present study we aim to identify new ABCG2+ pancreatic cell populations and to explore whether they exhibit properties of progenitor cells. We isolated and expanded mitoxantrone-resistant cells from pancreata of lactating rats by drug selection. These cells were characterized and maintained in different stages of differentiation using several cocktail media plus matrigel. Differentiation was assessed by RT-PCR, immunocytochemistry, electron micr... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2346642 Mon, 20 Apr 2009 04:00:00 +0100 2346642 http://www.medworm.com/index.php?rid=2283096&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20082441 Genome mining and biochemical analyses have shown that L. major possesses two pathways for cysteine synthesis - the de novo biosynthesis pathway comprising serine acetyltransferase (SAT) and cysteine synthase (CS) and the reverse transsulfuration (RTS) pathway comprising cystathionine β-synthase (CBS) and cystathionine gamma-lyase (CGL). The L. major CS (LmjCS) is similar to the type A CSs of bacteria and catalyses the synthesis of cysteine using O-acetyserine and sulfide with Kms of 17.5 and 0.13 mM, respectively. LmjCS can use sulfide provided by the action of mercaptopyruvate sulfurtransferase (MST) on 3-mercaptopyruvate (3-MP). LmjCS forms a bi-enzyme complex with Leishmania SAT (and Arabidopsis SAT), with residues K222, H226 and K227 of LmjCS being involved in the complex forma... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2283096 Wed, 18 Mar 2009 04:00:00 +0100 2283096 http://www.medworm.com/index.php?rid=2236724&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20082421 Lipid hydroperoxides (LOOHs) in oxidized LDL (oxLDL) are potentially atherogenic compounds. Recently, H2S was identified as the third endogenous gasotransmitter in the vasculature. Hydrogen peroxide is known to be destroyed by H2S. Assuming that H2S may also react with LOOHs, the results show that H2S can destroy LOOHs in oxLDL. LOOH-enriched LDL after H2S-pretreatment was not further oxidized by endothelial cells and macrophages and the ability of oxLDL to induce HO-1 in endothelial cells was abolished by H2S pretreatment. HPLC analysis showed that 9-HPODE (9-hydroperoxy-octadecadienoic acid), a compound found in oxLDL, was reduced to 9-HODE (9-hydroxy-octadecadienoic acid) in presence of H2S. Thus, H2S may act as an antiatherogenic agent by reducing LOOHs to the less reactive LOHs and co... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2236724 Thu, 05 Mar 2009 05:00:00 +0100 2236724 http://www.medworm.com/index.php?rid=2213316&cid=s_37616_60_f&fid=37616&url=http%3A%2F%2Fwww.biochemj.org%2Fbj%2Fimps%2Frefer.htm%3FMSID%3DBJ20081899 The c-Jun N-terminal kinase 1 (JNK1) plays a crucial role in the regulation of obesity-induced insulin resistance and is implicated in the pathology of type II diabetes. Its partner, JNK interacting protein 1 (JIP1), serves a scaffolding function facilitating JNK1 activation by mitogen-activated protein (MAP) kinase kinase 4 (MKK4) and MAP kinase kinase 7 (MKK7). For example, reduced insulin resistance and JNK activation are observed in JIP1 deficient mice. Based on the in vivo efficacy of a cell-permeable JIP peptide, the JIP/JNK interaction appears to be a potential target for JNK inhibition. The goal of this study was to identify small molecule inhibitors that disrupt the JIP/JNK interaction as an alternative approach to JNK inhibition. High throughput screening (HTS) was performed util... BJ Disease journals http://www.medworm.com/rss/comments.php?id=2213316 Wed, 25 Feb 2009 05:00:00 +0100 2213316